According to Wikipedia- Duplo is a version of Lego bricks from the well known Danish toy company, LEGO Group. Duplo bricks are eight times the size in volume, twice the length, height and width of traditional Lego bricks, and are easier to handle for younger children. Despite their size, they are still compatible with traditional Lego bricks. Since 1977, Duplo has made sets with figures, cars, and houses.
The Duplo product line changes from year to year — even the name Duplo had been dropped twice. Many Duplo sets have reappeared multiple times over the years. The most common sets are the farm, zoo, police station, fire station, airplane, and train sets.
Duplo link. I hope this helps those of you that aren't familiar with duplos/legos. My brothers adn sisters and I grew up playing with duplos, legos, little fisher price people (my mom has a HUGE HUGE collection of them now), and once in a while barbies. My sisters got really into barbies just as I was growing out of them.