For the Geo Quiz we are looking for a mountain lake that straddles Bolivia and Peru. It is a deep freshwater lake up around 12,000 feet above sea level, the largest, by volume, in South America. The Incas considered the lake a sacred place and for Bolivia and Peru it is still a national treasure that attracts thousands of tourists each year.
Lake Titicaca is the answer to the Geo Quiz. It is located high in the Andes on the border of Peru and Bolivia ans is a couple of hours away from the Bolivian city of La Paz. The lake faces serious environmental issues including pollution and over-fishing and receding water levels. Anchor Marco Werman talks to BBC's Mattia Cabitza who visited the lake.