Era
20th century
527
19th century
253
21st century
151
18th century
92
1945-
60
1989-
54
17th century
49
16th century
36
To 1500
36
1991-
30
Quaternary
28
1945-1989
26
1933-1945
22
2000-
22
Precambrian
21
Cretaceous
19
1564-1616
17
1960-
17
Early modern, 1500-1700
17
1976-2000
16
1889-1951
15
1949-
15
Civil War, 1861-1865
14
1724-1804
12
2001-2009
12
Eocene
12
Middle Ages, 600-1500
12
Tertiary
12
1844-1900
11
1990-
11
1856-1939
10
1976-
10
1993-
10
Primitive and early church, ca. 30-600
10
1770-1831
9
1882-1941
9
1925-1995
9
1929
9
1975-
9
1980-2020
9
1983-
9
Early church, ca. 30-600
9
1839-1914
8
1889-1976
8
1946-
8
1947-
8
Holocene
8
Pleistocene
8
1942-
7
1979-
7
more ...