Lake Titicaca makes a classic day trip from La Paz, lying only two hours' drive north-east. The lake is remarkably beautiful, with water and islands reminiscent of the Greek islands.

Only the snowcapped mountains in the background, the odd eucalyptus grove and the dip in temperature to -15C overnight reminds you that you are at 3800 metres on the highest lake of its size in the world.

Half of it belongs to Peru and you can see the Peruvian mountains off to the south-west, but the lake is so long that if you look north-west there's a flat horizon.