In 1987, BCEE launched a plan to extend the former casemate, so that it would connect the bank's four buildings that lie on the plateau. The possible usage of the tunnel itself was debated, and the idea was formed to turn the tunnel into a gallery. Construction began in 1992, and the gallery was opened in 1993. It is primarily dedicated to hosting works by more than a hundred Luxembourgian artists, particularly the photographer Edward Steichen, to whom a permanent collection is dedicated. However, the gallery also hosts retrospectives of other artists.