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The World Time Clock is one of the Alexanderplatz's most well-known features. It was constructed in 1969 as part of the square's redevelopment and has become a popular meeting point.
Weighing 16 tonnes and 10 metres tall, it features a revolving cylinder with the world's 24 time zones bearing the names of major cities in each zone. The mechanism constructed in a way which enables the current time in each zone to be read.
The clock is topped by a simplified model of the solar system, which revolves once a minute.