The LEGO DUPLO theme was introduced as far back as 1969 and is designed for children ages 1 to 5. It features DUPLO figures which are much larger than minifigures and DUPLO blocks which are about twice the length, width, and height of a standard System brick. Like LEGO System, DUPLO also has subthemes that are often junior versions of System themes, like Pirates and Castle and licensed themes like Disney and Super Heros.
1972 LEGO Sets
In 1972 The LEGO Group officially expanded to the United States. After a licensing disagreement with the Samsonite Corporation, LEGO USA was established in Brookfield, Connecticut and Samsonite ended production of LEGO products in the United States but continued production in Canada. As far as new parts and production, 1972 saw the release of the first boat hull, wing, propeller and helicopter rotor parts as well as new parts including the 1x6 arches. The train theme continued to grow and a number of notable train sets of 1972 included set 181 Train Set with Motor, 180 4.5V Train with 5 Wagons and 724 12V Diesel Locomotive.