From snowcapped, craggy Andean mountains and the vast plains of Los Llanos, to the lush tropical forests of the Amazon basin and rolling green valleys full of coffee, Colombia is a mind-blowingly beautiful and varied country. What's more, it harbors astonishing biodiversity, being the second most biodiverse country on earth after neighboring Brazil.

The Land

Colombia covers 1,141,748 sq km, roughly equivalent to the combined area of California and Texas (or France, Spain and Portugal). It is the 26th-largest country in the world, and the fourth-largest in South America, after Brazil, Argentina and Peru.

While most people assume that Colombia is just a tropical land, the country's physical geography is amazingly varied. The country's environment is generally divided into five habitat categories: wet tropical forests, dry tropical forests, tropical grasslands, mountain grasslands, and deserts and scrublands.

The western part, almost half of the total territory, is mountainous, with three Andean chains – Cordillera Occidental, Cordillera Central and Cordillera Oriental – running roughly parallel north–south across most of the country. A number of the peaks are over 5000m, making them higher than anything in the USA. Two valleys, the Valle del Cauca and Valle del Magdalena, are sandwiched between the three cordilleras. Both valleys have their own eponymous rivers, which flow north, unite and eventually empty into the Caribbean near Barranquilla.

Apart from the three Andean chains, Colombia features an independent and relatively small range, the Sierra Nevada de Santa Marta, which rises from the Caribbean coastline to soaring, snowcapped peaks. It is the world's highest coastal mountain range, and its twin summits of Simón Bolívar and Cristóbal Colón (both 5775m) are the country's highest.

More than half of the territory east of the Andes is vast lowland, which is generally divided into two regions: Los Llanos to the north and the Amazon River basin to the south. Los Llanos, roughly 250,000 sq km in area, is a huge open swath of grassland that constitutes the Orinoco River basin. Colombians say it is like an internal, green sea. The Amazon region, stretching over some 400,000 sq km, occupies Colombia's entire southeast and lies in the Amazon basin. Most of this land is covered by a thick rainforest and crisscrossed by rivers, and remains totally cut off from the rest of the country by road, though sadly this doesn't stop illegal logging.

Colombia also has a number of islands. The major ones are the archipelago of San Andrés and Providencia (a long way off in the Caribbean Sea, 750km northwest of mainland Colombia), the Islas del Rosario and San Bernardo (near the Caribbean coast), and Gorgona and Malpelo (along the Pacific coast).

Wildlife

This huge variety of climatic and geographic zones and microclimates has spawned diverse ecosystems and allowed wildlife to evolve independently. And how. Colombia claims to have more plant and animal species per square kilometer than any other country in the world. Its variety of flora and fauna is second only to Brazil's, even though Colombia is seven times smaller than its neighbor.

Animals

From pink dolphins to colorful parrots, tiny cats to giant rats, Colombia has some of the most unusual animal life on the planet. It has nearly 1700 recorded species of birds – 74 of which are native to the country – representing about 19% of all the birds on the planet. Colombia also has about 450 species of mammal (including 15% of the world's primates), 600 species of amphibian, 500 species of reptile and 3200 species of fish.

Some of the most interesting mammals include sleek cats such as the jaguar and the ocelot, red howler monkeys, spider monkeys, the three-toed sloth, giant anteaters, the goofy piglike peccary and tapir, and the hideous-looking capybara, or chiguiro, the world's largest living rodent that can grow to 48cm tall and weigh 55kg.

The waters of Colombia's Amazon are home to the famous rose-colored boto (Amazon River dolphin), the Amazonian manatee, and one of the most feared snakes, the anaconda (Eunectes murinus) that can grow to 6m.

Colombia's famous aviary includes 132 species of hummingbirds, 24 species of toucans, 57 types of colorful parrots and macaws, plus kingfishers, trogons, warblers and six of the world's seven vultures, including the Andean condor – a national symbol of Colombia.

There is also abundant marine life in the country's extensive river systems and along its two coastlines. The islands of San Andrés and Providencia boast some of the largest and most productive coral reefs in the Americas, now Unesco listed as the Seaflower Biosphere Reserve in order to protect the ecosystem. The reefs are considered among the most intact in the Caribbean and play an important ecological role in the health of the sea. They provide feeding and nesting grounds for four species of endangered sea turtles and numerous types of fish and lobster. It has been determined that the health of certain fish stocks in the Florida Keys hinges directly on their ability to spawn in the Colombian reefs. The island of Providencia itself is home to the Providencia black crab (Gecarcinus ruricola), a unique species of crab that lives on the land, but completes an extraordinary annual migration to the sea to lay and fertilize eggs.

Endangered Species

The vast savanna of Los Llanos is home to some of the most endangered species in Colombia. Among them is the Orinoco crocodile, which can reach 7m in length. According to the Wildlife Conservation Society, only 200 of these crocs remain in the wild in Colombia, making it one of the most critically endangered reptiles in the world, mainly due to the creatures' valuable skin. The good news is that between 2015 and 2016, over 40 juvenile Orinoco crocodiles were released into Tuparro National Park as part of the Proyecto Vida Silvestre program, which promotes conservation efforts in Los Llanos. Other endangered creatures from the region include the Orinoco turtle, giant armadillo, giant otter and black-and-chestnut eagle.

The cotton-top tamarin, a tiny monkey weighing just 500g, and its larger cousin, the brown spider monkey, are two of the most critically endangered primates in the world, according to the 2014 International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Other critically endangered or endangered animals on the IUCN list include Handley's slender mouse opossum, mountain grackle and the mountain tapir. And two of the Amazon River's most famous residents, the pink river dolphin and the Amazonian manatee, are considered vulnerable.

Note that some remote restaurants and bars offer turtle eggs, iguanas and other endangered species on their menus. It's also worth noting that the pirarucú (a fish popular in the Amazon basin region around Leticia) has been subject to overfishing; locals routinely ignore regulations preventing fishing for this species when it's spawning. These animals are endangered and eating them may hasten their extinction, so think before you order: there are normally other fish available on menus in the Amazon.

The Great Providencia Crab Migration

It truly is one of the most extraordinary sights you'll ever see: for a whole week in April the uniquely terrestrial Providencia black crab comes down from its habitat in the mountains and makes its way awkwardly towards the sea, where the females lay their eggs and the males then fertilize them, before returning inland shortly afterwards. During this time, the one road that rings this tiny Caribbean island is closed, and life for many becomes very static and even quieter than usual, with islanders only able to move around the island on foot.

A few months later, usually in July, the hatched juvenile crabs, still tiny, crawl out of the sea and head to the mountains. During this second migration the island shuts down again, and the sound of rustling is permanent day and night as the tiny crabs make their inelegant way up the hillside in their millions. If you're lucky enough to arrive on Providencia during either of these times, you're in for an unforgettable, if somewhat Hitchcockian, experience.

Plants

Colombia's flora is equally as impressive as its fauna and includes more than 130,000 types of plant, a third of which are endemic species. This richness does not convey the whole picture: large areas of the country, such as the inaccessible parts of the Amazon, have undiscovered species. It is estimated that, at a minimum, 2000 plant species have yet to be identified and an even greater number have yet to be analyzed for potential medicinal purposes.

Colombia has some 3500 species of orchids, more than any other country. Many of them are unique to the country, including Cattleya trianae, the national flower of Colombia. Orchids grow in virtually all regions and climate zones of the country, but are mostly found in altitudes between 1000m and 2000m, particularly in the northwest department of Antioquia.

Further up into the clouds you will find the frailejón, a unique, yellow-flowering, perennial shrub that only grows at altitudes above 3000m. There are some 88 species of frailejón, most native to Colombia. You'll find them in protected places such as Sierra Nevada de Santa Marta, Sierra Nevada del Cocuy and Santuario de Iguaque.

National Parks

Colombia has 59 national parks, flora and fauna sanctuaries and other natural reserve areas, all administered by the government's Parques Nacionales Naturales (PNN) de Colombia.

Unfortunately, simply declaring an area a national park has not stopped guerrilla activity, drug cultivation, illegal ranching, logging, mining or poaching. Most parks in the Amazon basin and along the Ecuadorian border should be considered off-limits. Other parks, such as Los Katios, a Unesco World Heritage Site near Darién Gap, are open but remain dodgy and access is limited; check the current security situation before proceeding.

On the bright side, many parks that were off-limits in recent years are now open for tourists and are included in our coverage. With the recent growth in tourism and ecotourism, the government is finally pumping pesos into its long-underfunded national parks system. New parks have recently opened and more are in the planning stages. Established parks are finally getting much-needed visitor amenities such as lodging and dining facilities, a rarity in Colombia.

This has not been without controversy. PNN has begun contracting with private companies to develop and operate tourist facilities inside some national parks, a move that some environmentalists fear will lead to overdevelopment. Some are concerned that prices will also increase and make the parks inaccessible to average Colombians. However, environmentalists have in recent years had some success checking such planned developments.

Colombia's most popular parks are situated along the country's pristine beaches. PNN Tayrona is by far Colombia's most popular national park, followed by Parque Nacional Natural (PNN) Corales del Rosario y San Bernardo and Parque Nacional Natural (PNN) Isla Gorgona.

Many other national parks offer just simple accommodations including basic cabins, dorms or campsites. Travelers wishing to stay overnight must book ahead with the PNN central office in Bogotá. There are also PNN regional offices in most large cities and at the parks. Most parks have an admission fee, payable at the entrance or at a regional PNN office.

It is always a good idea to check ahead of time with tour agencies and the parks department for up-to-date security and weather conditions for any park before visiting.

Private Parks & Reserves

In recent years the number of privately owned and operated nature reserves has increased. These are run by individual proprietors, rural communities, foundations and nongovernmental organizations. Many are just small, family reserves, sometimes offering accommodations and food. About 230 of these private parks are affiliated with the Asociación Red Colombiana de Reservas Naturales de la Sociedad Civil.

Yet another new player in the park scene is the corporation. Future parks might look a lot more like the new Parque Nacional del Chicamocha, near Bucaramanga. This for-profit, corporate-run resort opened in 2006, at a reported cost of US$20 million. In addition to hiking and trekking opportunities, this commercial theme park features dozens of restaurants, cafes, thrill rides, a zoo, cable cars and water park.

Environmental Issues

Many challenges remain, not least of which are the problems of climate change, habitat loss, and a loss of biodiversity through giant agribusiness megaplantations. The rapid push to develop a market-based economy and compete globally has put pressure on Colombia to build on its land and exploit its natural resources; these include farming, legal and illegal logging, mining and oil exploration. Such deforestation has increased the rate of extinction for many plant and animal species and destabilized soils, leading to the silting of rivers and devastation of marine species.

Even more troubling is the environmental impact of the illegal drug trade. Other illegal cash crops include marijuana and opium poppies. Attempts to stop farmers cultivating coca simply cause the producers to relocate. They move higher up the slopes and to the more remote, virgin forests of the Andes (aided by an increase in opium cultivation, which favors higher altitudes) and deeper into parks and the Amazon basin. In addition, antidrug efforts by the Colombian government (and, in large part, funded by the US war on drugs) have also taken some toll: the most common method of eradication has been aerial fumigation of coca fields; these hazardous herbicides destroy not just the coca plants, but surrounding vegetation as well, and no doubt seep into the watershed.

Sadly, the retreat of the FARC in many rural areas of Colombia has actually led to an acceleration in deforestation, as the rebels carefully controlled logging in order to keep their own locations covert. The FARC's surrender has left a power vacuum in many places and in 2016, deforestation jumped by an extraordinary 44% on the previous year to 178,597 hectares.

Green Fever

Colombia produces the largest percentage of the world's emeralds (50%; compared to Zambia's 20% and Brazil's 15%). Some estimate that the mines inside Colombia may actually contain up to 90% of the world's emerald deposits. This is good news for emerald prospectors but may not bode so well for the local environment – and perhaps Colombia as a whole. The fighting and destruction related to the production of these glamorous gems has had an impact on the country not so different from cocaine and heroin.

The main emerald-mining areas in Colombia include Muzo, Coscuez, La Pita and Chivor, all in the Boyacá department. Although the Muisca people mined emeralds in pre-Columbian times, the Spanish colonialists went crazy for the shiny green stones and greatly expanded the operations. They enslaved the indigenous locals to mine the gems and eventually replaced those workers with slave labor from Africa. Many of today's miners are the direct descendants of those slaves and live in only slightly better conditions.

The rich deposits in these areas have led to several environmental and social problems. Rampant digging has torn up the countryside and, in an attempt to find new digging sites or to improve their squalid living conditions, miners have continuously pushed further into the forest. Fierce battles have repeatedly been fought between rival gangs of miners, claiming lives and ravaging the mines. Between 1984 and 1990 alone, in one of the bloodiest 'emerald wars' in recent history, 3500 people were killed in Muzo. Yet 'green fever' continues to burn among fortune hunters and adventurers from all corners of the country and it may not stop until the last bewitching green gem is mined.