Jumping from the windows
In 1961 the houses on one side of Bernauer Straße were in the East, but the sidewalk in front of them was in the West. People jumped from their windows to escape before the windows were bricked up.
On Bernauer Straße the Wall ran right along the fronts of the houses, and some of its most dramatic escapes happened here. Here's what you're looking at, and what to listen for as you walk it.

In 1961 the houses on one side of Bernauer Straße were in the East, but the sidewalk in front of them was in the West. People jumped from their windows to escape before the windows were bricked up.
Several escape tunnels were dug beneath this street. In 1964, 57 people crawled to the West through "Tunnel 57".
The Church of Reconciliation stood inside the border strip, unreachable for its own parish. East Germany blew it up in 1985; a chapel made of rammed earth now stands on its site.
Yes, the open-air memorial, the Visitor Center and the Documentation Center are free.
At Bernauer Straße you can see a preserved section of the Wall with the border strip and a watchtower behind it.
It runs about 1.4 kilometers along Bernauer Straße.