Berlin Tools
The old airfield is 2.2 km from the west fence to the east fence, it has ten public gates, and its closing time moves every month. Set the month, drag the hour, say what you came for, and the map answers the only question that matters at the fence: which gate, and can you still get through it.
Field outline, runways and gate positions from OpenStreetMap contributors, ODbL. Opening times and entrance list from Grün Berlin.