The south-west of Bolivia is a land of extremes: high altitudes, colossal views and mind-bending landscapes. Little wonder, then, that this rail journey finds its way on to so many travel itineraries. Yet the Expreso del Sur is rather misleadingly named - it takes some seven hours to cover the 300km between mining town Oruro and the salt flats hub of Uyuni. Luckily, its twice weekly afternoon departure (2.30pm Tue & Fri) means you can enjoy the trip during daylight hours, as the views are spellbinding.
Oruro (a three-hour bus ride from La Paz) is best visited at carnival time, when La Diablada sees locals dressed as demons hit the streets in early November for a riotous week-long festival. At other times, a side-trip to the flamingo-frequented waters of Lake Uru-Uru - which you'll later pass - is well worth it as a precursor to the altiplano vistas through which the train trundles.
But the big draw here is the vast salt flats of Uyuni - the largest in the world. It is one of Latin America's most incredible natural spectacles, and often takes on a very different feel between December and April, when seasonal rains can turn its cracked, crusty surface into a giant liquid mirror of the sky.
From here on, it's an overnight trip through the cowboy country of Tupiza (good for treks and horseriding) to Villazón on the Argentine border. But there are no sleeper carriages and it can get cold on board, so pack accordingly.
