Adventure Playground, Urban park in Berkeley, California, US.

Adventure Playground is an urban park in Berkeley, California, where children can build their own play structures using real tools and recycled materials under adult supervision. The park sits on the shore of the San Francisco Bay and also has tire swings, zip lines, and a mud area.

Adventure Playground opened in 1979 at the Berkeley Marina, modelled on the ideas of Danish architect Carl Theodor Sørensen, who set up scrap-junkyard playgrounds in Copenhagen during its occupation in World War II. The model, sometimes called a "junk playground", gives children tools and materials to build with. Legal liability has kept such playgrounds rare in the United States; Berkeley's is one of only four.

Children here use real tools and recycled wood to build whatever they want, guided by staff who let them take the lead. Each visit looks different because kids leave their structures behind for others to change or tear down.

The park is open every day except Monday, from 10 a.m. to 5 p.m., and entry is free. Children under six must be accompanied by an adult, and all children should be supervised at all times. Wear clothes that can get dirty, since mud and sawdust are part of the experience.

Structures built by children are left standing after each visit, so the next group can change, add to, or tear them down entirely. This means the playground never looks the same way twice.