Berlin Wall

What is it: After the Second World War, Germany was divided into parts that were assigned to the Allies. The Soviet Union took the East part of Germany and it became the GDR. The Western Allies took the West. However, Berlin had also been divided up equally, even though it was located in the Eastern section. So in 1961 the GDR built a wall to isolate West Berlin from the rest of East Germany. The Wall was 87 miles long and stood until 1989. 100,000 people tried to escape during those 28 years and many were killed in the attempt.
What's it like: It's a weird one, because it's not actually there anymore. There are chunks of it dotted around the city and Checkpoint Charlie has been recreated, but you have to imagine the scale and the impact of it, and what it would have been like to live with an enormous wall in your city.
Where: Berlin, Germany
When: March 2007
How: Pete had always wanted to visit Colditz, so we did a tour of former East German cities - we started in Leipzig, then Dresden, and then finally Berlin. We also visited the Reichstag (221) and the Brandenburg Gate (435).
Worth noting: There's a Berlin Wall Trail that you can do by bike and a memorial museum - we didn't do either of them but I think they'd be useful.
Place in the 2015 edition: 63

Did it deserve to lose its place in the 2020 top 500: No. It's very odd.