What is the highest navigable lake on Earth?

Lake Titicaca is the highest navigable lake on Earth.

The lake sits in the Andes on the border of Peru and Bolivia, at a surface elevation of about 3,812 metres above sea level. Its size and depth allow substantial vessels to operate there, which is why it holds the standard “highest navigable lake” distinction.

The wording has an important qualification: it usually refers to navigation by commercial or sizeable watercraft. Much smaller lakes exist at higher elevations, including crater lakes on high volcanoes. Lake Titicaca is therefore not the highest lake of any kind, but it is the conventional answer to this quiz question.

Titicaca is also South America’s largest lake by surface area and water volume, although Lake Maracaibo is larger in area if counted as a lake; it is generally classified as a tidal bay. The lake’s waters are slightly brackish rather than perfectly fresh.