Q 01/05

Which body of water is the world's largest lake, though it is usually called a sea?

A) Caspian Sea

B) Black Sea

C) Aral Sea

D) Dead Sea

Answer · why

A) Caspian Sea

It is bordered by five countries and is famous for caviar and oil, and its shores are below sea level.

Q 02/05

Which body of water is the deepest in the world, plunging more than a mile down?

A) Tanganyika

B) Baikal

C) Crater

D) Superior

Answer · why

B) Baikal

Its sheer depth means it holds 22-23% of the world's fresh surface water, more than all the North American Great Lakes together.

Q 03/05

The world's deepest lake, in Siberia, is also its oldest. Roughly how old is it?

A) 1-2 million years

B) 5-8 million years

C) 25-30 million years

D) 100 million years

Answer · why

C) 25-30 million years

Most lakes are geologically young; this one sits in an active rift and just keeps getting deeper.

Q 04/05

What is the freshwater seal species found only in Lake Baikal called?

A) Ringed seal

B) Selkie

C) Nerpa

D) Ladoga seal

Answer · why

C) Nerpa

Its main prey is the golomyanka, a translucent oily fish that makes up the lake's biggest fish biomass.

Q 05/05

Often called the highest navigable lake in the world, Titicaca sits on the border of which two countries?

A) Bolivia and Chile

B) Chile and Argentina

C) Ecuador and Peru

D) Peru and Bolivia

Answer · why

D) Peru and Bolivia

Its surface is 3,812 metres above sea level, and the Uros people live on islands they build from cut totora reeds.