REMOVE

1. Timeline
2. United States
3. Canada
4. Europe

WHAT

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

WHERE

1. Mexico (6)

WHO

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

WHEN

1. 1842 (6)