"he was astonished to glimpse the plump silhouette of the Brandenburg Gate"

The Brandenburg Gate, one of Berlin's most famous features, was built between 1788 and 1791.  Until the erection of the Berlin Wall in 1961, vehicles and pedestrians could pass through it.  The wall effectively closed the Gate off to both West and East Berlin.

The Brandenburg Gate
Public DomainThe Brandenburg Gate just before the Berlin Wall went up