Tokyo Station is the main transportation hub of Tokyo, connecting the metropolis to every other major city across the country. It is also a wonder in itself, from its retro red-brick façade on the Marunouchi side to its extensive, multi-storied shopping malls on the inside and several historical secrets hidden in plain sight.

Located near the Yaesu Exit on the Keiyo Line side, the so-called R.T.O. Relief is a prime example of such oft-overlooked pieces of history at Tokyo Station. Most passengers walk past it without a single look, and those few who do give it a brief glance typically dismiss it as nothing special, just an enlarged relief map of Japan behind a glass case.

Except, of course, that’s not the case—it’s a lot more than just a common mural. The map is actually a leftover from the Allied occupation of Japan, “RTO” standing for Railway Transportation Office, established in 1947 under the direction of General Douglas MacArthur.

During the construction of the office, one worker suggested that it should have some feature that would amaze the Allied Forces. Designed by architect Junpei Nakamura, the relief map of Japan was created and adorned R.T.O.’s waiting room inside the Tokyo Station building. It illustrates many of Japan’s iconic landmarks such as Mount Fuji and the Yabusame ceremony in Kamakura, naming each site in Roman alphabet.

After the Allied occupation came to an end, the R.T.O. Relief fell into disuse at some point, until it was rediscovered by the station staff during the Marunouchi building’s restoration around 2012. The artwork was reinstalled at its current location and has stood there since, a little-appreciated piece of Japan’s post-war transportation history.