Ordinarily a tour of a storage facility wouldn’t be all that exciting. But the storage facility of London’s Museum of Transport is something entirely different. The museum depot holds the 90 percent of the transport museum’s collection that is not on display—a mishmash of some 320,000 items showing the history of London’s transportation system.

Open to the public just twice a year, the nearly 65,000 square feet storage space gives a behind-the-scenes look at the museum’s collection, its curation process, and its preservation. There, curators and volunteers catalog and conserve objects from the collection, which shows the evolution of urban transportation over the last 150 years.

Tours of the facility give an up-close look at the museum’s poster collection, filled with transportation posters created by notable artists such as Man Ray and Edward McKnight Kauffer; its vehicle collection, including a restored 1938 Tube train; and a look at the design process involved in creating signage for the transit system.

The Museum of Transport describes the depot as providing “a living link of how London itself has evolved since the early 19th century.” The story of how a city moves, how it gets its citizens from place-to-place, and the evolution of those methods is all part of a much larger story of technology, art, and industry in the European metropolis.