3

Amazing Earth - Part 1

4

Earthquakes

3

The Earth

3

Amazing Earth - Part 2

4

Extreme Earth

3

Pollution

3

Canyons of the World

3

Mercury

4

Lightning

3

Harbors of the World

2

Respect

3

Saturn

2

Frozen Ground! Tundra

4

Forbidden City, China

4

Steppe

3

Senses

3

Gravity

3

Coastal Plains of the World

4

Tornadoes

2

Ecosystems

3

Rivers of the World

3

Sinkholes of the World

3

Magnetism

3

Coral Reefs of the World

3

Drainage Basins of the World

1

Animals and their homes

2

Solar System

2

Natural Disasters

3

Trenches of the World

3

Lakes of the World