Berlin's other wall
No, it's not that wall, but in many ways this unassuming section of bricks and mortar is just as significant.
In 1980, Lech Walesa clambered into a shipbuilding yard in Gdansk, Poland, to organise a strike which would lead to the formation of Solidarity, the Soviet bloc's first independent trade union.
A small section of the wall he scaled - a gift to Germany from the Polish government - is nestled rather inconspicuously alongside the Reichstag. And there's a certain irony in the fact that, in a city where fragments of a far better-known barrier are a major tourist attraction, this particular monument seems to go largely unnoticed.
A pity, because as the attached tablet makes clear, Walesa's actions were instrumental in the larger chain of events that would usher in the end of communism in Eastern Europe.
In other words, without the history this overlooked fragment of masonry represents, the Berlin Wall itself might still be standing today.
Polish Solidarity wall: North-east corner of the Reichstag building, Reichstagufer / corner Friedrich-Ebert-Platz, 10117 Berlin