The Western Museum of Mining & Industry is a museum in Colorado that contained a Labyrinth entrance in it. The entrance was destroyed along with the Labyrinth itself when Nico di Angelo took Daedalus' spirit out of his automaton body.

Percy Jackson and the Olympians

The Battle of the Labyrinth

Rachel spots an entrance to the Labyrinth while being driven around the area. Once she finds the entrance, Percy, Annabeth, Nico, and her enter the Labyrinth once again.

Locations (CHB)
Magical Locations: Olympus | Camp Half-Blood | Camp Jupiter | Aeolia | C.C.'s Spa and Resort | Daedalus' Workshop | Lotus Hotel and Casino | Mount Othrys | Ogygia | Pan's Cave | Sea of Monsters | The Labyrinth | Tartarus
Cities, States, and Towns: Alaska | Bar Harbor | Chicago | Detroit | Gila Claw | Jamestown | Long Island | Manhattan | New York City | Quebec | San Francisco | Vancouver | Westport
Other Locations: Apennine Mountains | Aunty Em's Gnome Emporium | Crusty's Water Bed Palace | Empire State Building | Gateway Arch | Grand Canyon | Greece | Hoover Dam | Junkyard of the Gods | Mount Saint Helens | Polyphemus' Island | ROFL | Rome | Triple G Ranch | Waterland | Mount Etna | Mount Diablo | Mount Tamalpais | Pikes Peak