Checkpoint Charlie: the divided city's scar
The Cold War crossing, the longest stretch of inner-city Wall, and the ground where the Gestapo ran the Reich. This is a Claude-drafted route awaiting the editor's walk.

1. Checkpoint Charlie
The rebuilt guardhouse and the sandbags are a replica — the real one is in a museum — but the spot is the spot. Read the famous sign first: 'You are leaving the American sector,' in four languages. The actors charging for photos are not part of the history; walk past them.

2. The 'you are leaving' sign and Friedrichstraße line
Look down: a double row of cobbles runs across Friedrichstraße marking where the Wall stood. You can follow this line, set into streets all over the city, but here it cuts straight through the busiest crossing of the Cold War.

3. Topography of Terror
On the ground where the Gestapo and the SS ran their headquarters from 1933 to 1945. The documentation centre is free and unflinching. Give it more time than you planned; this is the dark engine room behind every other site on this walk.

4. The Wall along Niederkirchnerstraße
Outside the documentation centre runs the longest surviving stretch of inner-city Wall — pitted and gap-toothed where souvenir hunters chipped it away. The original border ran exactly here, between the Gestapo site and the building opposite.

5. The former Reich Aviation Ministry
Across Niederkirchnerstraße, a vast stone block: Göring's 1936 Aviation Ministry, one of the largest Nazi buildings to survive intact. The GDR ran its government from it; today it's the Finance Ministry. The architecture tells the whole German century in one facade.

6. Gendarmenmarkt
End on what's often called Berlin's most beautiful square — the Konzerthaus between the matching German and French cathedrals. After the morning's weight, a deliberate change of key. Stadtmitte (U2/U6) is a few steps off the square.

Checkpoint Charlie: the divided city's scar