Era
19th century
4,311
20th century
3,944
Early works to 1800
780
Civil War, 1861-1865
644
18th century
601
To 1800
482
1728-1779
470
21st century
424
1900-1999
416
1786-1847
411
1800-1899
390
1800-1870
389
1939-1945
378
Quaternary
358
16th century
343
17th century
323
1254-1323?
322
1945-
286
Revolution, 1775-1783
277
1480-1521
251
1868-1912
243
1874-1922
206
From 2 million years ago
201
1861-1930
197
1951-
189
1870-1945
182
1469-1524
175
Cretaceous
167
1700-1799
162
Nineteen tens
158
1856-1920
154
Period of discoveries, 1385-1580
153
1304-1377
152
1394-1460
138
1914-1918
137
Ottoman Empire, 1288-1918
135
1990
133
1861-1865
132
Paleozoic
130
1500-1599
129
2000-2099
123
1872-1928
120
-1521
117
Precambrian
117
1900 - 1999
110
1870-
105
1879-1962
105
To 1500
105
Cenozoic
97
1821-1890
95
more ...