To understand how one misread note could bring down one of the most heavily fortified borders in human history, you need to understand what the Berlin Wall actually was and why it existed.
After the Second World War ended in 1945, Germany was divided into four zones, each controlled by one of the Allied powers — the United States, Britain, France, and the Soviet Union. Berlin, deep inside Soviet-controlled territory, was similarly divided.
Over the following years the division hardened into some