Why is Boise known as the "City of Trees?" One of the greenest cities in the US, Boise is dotted with expansive parks, many of which are connected by the 20-mile "Greenbelt" along the Boise River. The city is also close to the vast Boise National Forest. With over 2.5 million acres of woodland, mountains, rivers and lakes, you could spend your whole weekend break in the forest, hiking through stunning scenery or white water rafting. But it would be a shame to miss out on the attractions in the center of Boise, including the Bronco Stadium, home to the Boise state college football team. Visit the Old Idaho State Penitentiary, which now operates as a museum and allows visitors to experience what life was like in solitary confinement, as well as seeing where Death Row inmates used to meet their end. If you're really brave, you can even join the museum's late-night paranormal tours, or encounter spirits of a different kind by heading out to enjoy Boise's vibrant nightlife.