REMOVE

1. Europe
2. Boynton, G. W.

WHAT

1. Data Visualization (6)
2. Historical (6)
3. Historical Atlas (6)
4. Timeline (6)

WHERE

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

WHO

1. Holgate, Jerome B., 1812- … (6)
2. J.B. Holgate (6)

WHEN

1. 1842 (6)