Dodecanese

Nisyros sits on a volcanic fault line that curves around the southern Aegean. While 25,000 years have passed since the volcano that formed it last erupted, it’s officially classified as dormant rather than extinct. Its summit originally stood around 850m tall, but three violent eruptions 30,000 to 40,000 years ago blew off the top 100m and caused the centre to collapse. White-and-orange pumice stones can still be seen on the northern, eastern and southern flanks of the island, while a large lava flow covers the entire southwest around Nikea.

The islanders call the volcano Polyvotis. Legend has it that during the battle between the gods and Titans, Poseidon ripped a chunk off Kos and used it to trap the giant Polyvotis deep beneath. That rock became Nisyros and the roar of the volcano is Polyvotis' angered voice.

Visitors keen to experience the power of the volcano head by bus, car or on foot into the island’s hollow caldera, a vast and otherworldly plain that was home to thousands of ancient farmers. Ruined agricultural terraces climb the walls, while cows graze amid sci-fi-set rocks.

The southern end encloses several distinct craters. Get there before 11am and you may have the place to yourself. A path descends into the largest crater, Stefanos, where you can examine the multicoloured 100°C fumaroles, sometimes listen to their hissing and smell the sulphurous vapours. The surface is soft and hot, making sturdy footwear essential. Don’t stray too far out, as the ground is unstable and can collapse (at the time of research, the centre was roped off).

An obvious track leads to the smaller and wilder crater of Polyvotis nearby. You can’t enter the caldera itself, and the fumaroles are around the edge here, so take great care.

A glorious mixture of Byzantine, Turkish and Italian architecture, erected on top of far more ancient and largely unidentifiable remains, the Old Town is a world of its own. In theory, it consists of three separate sections, though casual visitors seldom notice the transition from one to the next. To the north, sturdy stone mansions known as inns line the arrow-straight streets of the Knights’ Quarter. These strikingly austere edifices, built to house knights from specific countries, were laid out by the medieval Knights of St John. South of that, the Hora, also known as the Turkish Quarter, occupies the central bulk of the Old Town. This tangle of cobbled alleyways is now the main commercial hub, packed with restaurants and shops interspersed between derelict mosques and Muslim monuments, and, regrettably, bursting with visitors every day in summer. The Jewish Quarter in the southeast, which lost most of its inhabitants during WWII, is now a sleepy residential district.

Visitors can walk atop the central stretch of the imposing 12m-thick ramparts that still protect the landward side of the Old Town, and descend at various points into the wide, deep moat that encircles them, filled with lush gardens and perfect for a relaxed stroll.

Of the nine gateways to the Old Town, the busiest and most dramatic are the northernmost two, closest to the New Town. Liberty Gate, the nearest to Mandraki Harbour and the taxi rank, leads to a small bridge and the main tourist areas, while the atmospheric D’Amboise Gate, further inland, crosses an especially attractive section of the moat en route to the Palace of the Grand Master.

Walking is the reason many people, especially repeat visitors, come to Tilos. There are around 54km of trails in Tilos, to varying degrees of marking. Keen walkers should get their hands on the outstanding guide, Exploring Tilos: a Walkers' Guide to the Island by Jim Osborne (available online and in some local shops). It outlines in great detail every trail, and is a delight to follow, given the accuracy of visual cues and grading of each walk, from easy to difficult.

One well-maintained and very scenic 3km walk leads north from Livadia to Lethra Beach, an undeveloped pebble-and-sand cove with limited shade. Follow the tarmac behind the Ilidi Rock Hotel, at the northwestern end of the port, to find the start of the trail. Returning via the picturesque Potami Gorge brings you to the main island highway. (Note, however, at the time of research, part of the trail had been destroyed due to winter storms; check with other walkers before heading out).

A longer walk leads to the small abandoned settlement of Yera and its accompanying beach at Despoti Nero. Simply follow the road south from Livadia around the bay and keep going beyond the Church of Agios Ioannis at the far eastern end. Allow half a day for the full 6km round trip.

Located on Kastellorizo’s remote southeast shore, this extraordinary cave is famous for its mirror-like blue water. To get there, you must take one of around four competing water taxis in Kastellorizo. It's a 45-minute experience including the 15-minute journey there (and back) plus around 15 minutes in the cave itself. Boats will not enter if conditions are not right. The entrance – a distance of around two metres – is so low that you must lie down in the boat.

A group of passionate, young Kalymnians recently created Kalymnos Experience to offer alternative local experiences, some of which are difficult to do on your own. Options include nature walks, yoga, rock climbing, and scuba diving, to herb walks in the mountains (ending with a practical lab to prepare your own concoctions!). There's a weekly schedule or they'll arrange... almost anything!

Beautiful Symi is guaranteed to evoke oohs and aahs from ferry passengers before they even get off the boat. The first sight of Gialos harbour, framed against an amphitheatre of pastel-coloured houses rising on all sides, is unforgettable. It’s all thanks to the Italians, who ruled the island almost a century ago and established the neoclassical architectural style that Symi has followed ever since.

Although Symi is far from small, it's mostly barren and the only settlements are Gialos, the old village of Horio, which sprawls over the hilly ridge behind, and Pedi, down in the valley beyond. One road runs all the way to the monastery at Panormitis, near Symi’s southern tip. The rest of the island is largely deserted, but it's surrounded by blue coves and small beaches.

Culturally, it's a little light on (beyond a couple of museums). But nobody seems to worry; there's enough here.

As this immense 11th-century monastery-cum-fortress remains active, only a small portion is open to visitors. The entrance courtyard leads to a sumptuously frescoed chapel, fronted by marble columns taken from an ancient temple. Don’t expect to attend a service; daily worship is at 3am! The museum of church treasures upstairs displays the original edict establishing the monastery, signed by the Byzantine emperor in 1088.

Between 1912 and 1948, when the west-coast port of Lakki was a significant Italian naval base, the town was transformed beyond recognition by the construction of grandiose administrative and military buildings and homes for officers. The result is extraordinary. The prevalent architectural style, now classified as streamline moderne, started out resembling art deco and ended up distinctly more fascist. It's worth wandering the streets to view houses (those you might consider contemporary are actually from that period). Otherwise, it's a marina. It's best as a visit, not as a base.

Few moments can beat rounding a curve in the mountain road to receive your first glimpse of this mist-blown eyrie of pastel-coloured houses. Olymbos clings precariously to the summit of Mt Profitis Ilias (716m), as if flung there by a Titan’s paw. Thread your way along its wind-tunnel alleys, passing old ladies in vividly coloured traditional dress, and you may feel as though you’ve strayed onto a film set. Some locals even speak with a dialect that still contains traces of ancient Dorian Greek.

It's considered to be the most traditional of all places in Greece; some of Olymbos' local ladies still wear their stunning hand-spun jackets and floral headgear. And the views – 'jaw-dropping' just doesn't cover it – will leave you spellbound as the earth plunges dramatically metres from your feet. Try and arrive in late afternoon or early morning to have the place to yourself.