The Peru Trip

Lake Titicaca is "the world's highest navigable lake" at 3,860m.
You might think, as I did, that if a lake's not navigable they're using the wrong craft, but you'd be wrong, as I was.
The distinction between a lake and a sea is a tricky one too. Even the authorities don't seem to define it consistently. However, it is jolly high.

Don't fall in here! - It's dirty!