Season
- Season 0 1984-09-24
- Season 1 1983-10-30
- Season 2 1984-05-06
- Season 3 1984-11-04
- Season 4 1985-09-15
- Season 5 1986-10-05
- Season 6 1987-09-20
- Season 7 1988-09-18
- Season 8 1989-10-01
- Season 9 1991-01-06
- Season 10 1991-11-24
- Season 11 1993-01-03
- Season 12 1994-02-20
- Season 13 1994-11-27
- Season 14 1996-01-14
- Season 15 1996-10-06
- Season 16 1997-10-19
- Season 17 1998-10-11
- Season 18 1999-10-03
- Season 19 2000-10-08
- Season 20 2001-10-07
- Season 21 2002-10-13
- Season 22 2003-10-12
- Season 23 2004-10-14
- Season 24 2005-10-19
- Season 25 2006-10-18
- Season 26 2007-04-04
- Season 27 2008-01-04
- Season 28 2008-11-11
- Season 29 2009-10-28
- Season 30 2010-07-08
- Season 31 2011-08-01
- Season 32 2012-07-19
- Season 33 2013-05-17
- Season 34 2014-04-11
- Season 35 2015-02-24
- Season 36 2016-04-14
- Season 37 2017-03-20
- Season 38 2018-03-31
- Season 39 2019-04-07
Natural World
7.06 60 minutes 
