Berlin's mayor urges Trump to rethink the US southern border wall

Berlin was once the site of one of the world's most famous walls. Now, its mayor is warning President Donald Trump not to build one along the U.S. southern border.

Mayor Michael Müller said in an open letter, "We Berliners know better than most the pain caused when a whole continent is split by barbed wire and walls. ... I call on the president of the USA not to go down that road to isolation and ostracism."

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Berlin was split in two after the end of the second World War. The Berlin Wall was built in 1961 to stop defectors from leaving Soviet-controlled East Berlin for the more prosperous West Berlin. It was eventually demolished in 1989.

The plea for Trump to reconsider his new wall project appears to be too late. He already signed an executive order to start construction.