4

Chip's Tips on Equatorial Guinea

4

U.S.S. Arizona Memorial at Pearl Harbor

3

Friction

3

Venus

4

Chip's Tips on United States

2

Four Seasons! Deciduous Forest

4

Father's Road Trip

4

Savanna

4

The Pygmy People

4

Taiga

4

Famous Americans: Abraham Lincoln

4

Famous Americans: Thomas Jefferson

4

Deciduous Forest

4

Chip's Tips on Yemen

4

Washington Monument

4

Maddy's Washington, D.C. Diary

3

Mars

4

Maddy's Missouri Diary

4

Tropical Rainforest

2

Treeless Plains! Steppe

2

Country Flags of Africa

4

Chip's Tips on Oman

3

Mercury

4

Steppe

4

Mount Rushmore

4

Montane Forest

4

Kremlin, Russia

2

Warm Grasslands! Savanna

3

Martin Luther King, Jr.

4

Maddy's North Carolina Diary