A New Charlie

When I first visited Berlin -- in 1972 -- you could enter East Berlin at Checkpoint Charlie. You had to return the same day. The Econtel hotel clerk told me I could find Checkpoint Charlie near the Kochstrasse U-Bahn station.
Checkpoint Charlie is now a souvenir stand. It also would be a good locale for a FotoMat.
A new, more practical, use for old DDR passports