The get together takes place at the tower of the Frankfurter Tor on Thursday, 6 - 8 pm. You can easily get there by subway. The station is "Frankfurter Tor" (brown line U5), and the tower is at the South-West corner of the crossroads.
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If you start form Hilton Hotel, take the red line U2 (direction "Pankow") and change at "Alexanderplatz" to the brown line U5 (direction "Hönow"). The whole trip should take about 15 minutes. Alternatively, you can take a taxi which should be about 10 Euros from Hilton Hotel.