The story of LEGO starts in 1932 when the carpenter Ole Kirk Christiansen began to make wooden toys in his workshop in Billund, Denmark. A few years he named his company LEGO. This comes from the Danish words 'leg godt', which means 'play well'. In 1949 the LEGO company introduced the well known construction bricks we all know now.
In 1957 the round tube inside the hollow brick was introduced, allowing to connect the bricks to each other in more ways. The quality of the type of plastic used for the bricks was not very well in that time, causing the reputation of LEGO to deteriorate. In 1963 the company started to use much better quality plastic, what dramatically increased the LEGO bricks. This plastic, Acrylonitril Butadieen Styreen (ABS), is still in use today.
Lots of other type of bricks were introduced throughout the years, as well as special series like 'Lego Trains', town and city, space, pirates, the wild west, etc... For the younger children DUPLO was introduced and LEGO Technic and LEGO Mindstorms "Robotic Invention Systems" is for ages up to 99+.
Because of the ability to connect all type of LEGO bricks to each other the only limitation building with LEGO is one person's fantasy.
For the whole family to visit, there are some very nice Legoland themeparks throughout the world: of course in Billund (Denmark), but also in England, Germany and in the USA (California and Florida).
You can visit the LEGO wesite here and find more information about the Legoland themeparks here.