1900s
1910s
1920s
1930s
1940s
1950s
1960s
1970s
1980s
1990s
2000s

15th
16th
17th
18th
19th
20th
21st
22nd
23rd
24th
25th

Categories

Categories:

Protected areas established in the 20th century
1950s establishments
1950s in the environment
Protected areas by decade of establishment