The nearest thing Bolivia has to Peru’s Machu Picchu is this remote, rarely visited site (meaning ‘Land of the Inca’), 132km east of Cochabamba on a flat mountain spur above the Río Machajmarka. This was the easternmost outpost of the Inca empire; after Tiwanaku it’s Bolivia’s most significant archaeological site. The most prominent feature is the immense stone fortification that sprawls across alluvial terraces above the river, but at least 50 other structures are also scattered around the 30-hectare site.

Incallajta was probably founded by Inca Emperor Tupac-Yupanqui, the commander who had previously marched into present-day Chile to demarcate the southern limits of the Inca empire. It’s estimated that Incallajta was constructed in the 1460s as a measure of protection against attack by the Chiriguanos to the southeast. In 1525, the last year of Emperor Huayna Capac’s rule, the outpost was abandoned. This may have been due to a Chiriguano attack, but was more likely the result of increasing Spanish pressure and the unraveling of the empire, which fell seven years later.

The site is on a monumental scale; some researchers believe that, as well as serving a defensive purpose, it was designed as a sort of ceremonial replica of Cuzco, the Inca capital. The site’s most significant building, the kallanka, measures a colossal 78m by 26m. The roof was supported by immense columns. Outside it is a large boulder, probably a speakers’ platform. At the western end of the site is a curious six-sided tower, perhaps used for astronomical observation. On the hilltop, a huge zigzag defensive wall has a baffled defensive entrance.

The ruins were made known to the world in 1913 by Swedish zoologist and ethnologist Erland Nordenskiöld, who spent a week at the ruins measuring and mapping them. However, they were largely ignored – except by ruthless treasure hunters – for the next 50 years, until the University of San Simón in Cochabamba launched its investigations.

At Pocona, 17km from the ruins, there’s an information center and a small exhibition of archaeological finds from the site.

Without your own transportation or a guided tour, visiting Incallajta will prove inconvenient at best. If you can’t arrange lodging in private homes or prefer the outdoors, you can camp at the site next to the ruins; be sure to take plenty of water, food and warm clothing, and have the proper gear.

Cochabamba agencies run day trips to Incallajta; most recommended is El Mundo Verde Travel, which adds a visit to the colonial village of Chimboata and will do the trip for one or two, and, of course, larger groups. Bolivia Cultura is another option. Beware of tours that seem suspiciously cheap or that involve 'trekking.' That usually means getting a cab part way and walking a good distance to the site.