REMOVE

1. Data Visualization
2. Timeline
3. Historical Atlas
4. J.B. Holgate

WHAT

1. Historical (6)

WHERE

1. Canada (6)
2. Europe (6)
3. Mexico (6)
4. United States (6)

WHO

1. Boynton, G. W. (6)
2. Holgate, Jerome B., 1812- … (6)

WHEN

1. 1842 (6)