Deutsche Bundespost Berlin Kongresshalle 14th Annual Congress - 1962

DEUTSCHE BUNDESPOST BERLIN on 3 March 1962 issued a First Day Cover stamp (here, 1 Pf. block of 6 + 1 international) of the Kongresshalle (Congress Hall)" marking their 14th Annual Congress. The stamp for this release was  printed on fluorescent paper, which is written vertically to the left of the cachet.

The cachet is perhaps more interesting given the Brandenburg Gate is cordoned off with Concertina wire. The caption below the photo is more telling, insomuch as the date, 13 August 1961,  is when erection of the Berlin Wall commenced. Behind the wire is the now historic sign that states,  "Achtung! sie verlassen jetzt West Berlin (Attention! You are leaving now leaving the West Berlin)."