As President Donald Trump spoke last week in Warsaw, Poland, cable news cameras panned across the raucous crowd bused in by the countrys right-wing government to cheer him on.

Amid the waving red-and-white Polish flags, a lone man over 4,000 miles from the U.S. South, from the land of Jim Crow, the Ku Klux Klan and slavery could be seen holding the Confederate flag.

There was some frightening symbolism to it: a 150-year-old emblem of white supremacy at a seemingly all-white rally for a white U.S. president speaking in dire, white nationalist tones about defending Western civilization.

But how did a flag born out of the American Civil War end up at a political rally in Poland in 2017? Groups across Europe have embraced the flag for their respective causes for years, and experts say some of its European fans dont understand what the rebel flag really represents in U.S. history.