It wasn't until 1978 that Lego introduced it's first themes. The first three were Town, Castle and Space. The next to be released were Boats and Trains and were
made to serve as complements to the Town theme. These 5 were dicontinued in 1999.
Currently there are 43 themes in production. There have been a further 107 Lego themes in the past, which have already been discontinued.
The current top 5 selling themes are..