Two aliens come back to earth to check up on humans, who they once helped overcome global warming and general extinction of all life due to contamination, only to find out that some things may still need a change.
2021
1984
2003
2024
2002
1972
2001
1971
1956
2006
1991
2015
1927
1979
1997
2007
1929
1995
1977