Clemon Jimerson still remembers his first time on the beach in Biloxi, Miss. It was April 24, 1960 – Easter Sunday – and Dr. Gilbert Mason, a local physician, had organized a gathering of more than 120 people on three sections of the 26-mile shoreline.

Jimerson was 14 years old at the time, and he marked the occasion with a brand new swimsuit and a top-of-the-line, gold-banded Elgin watch.

Jimerson lived just two miles from the beach, but Jim Crow laws barred him and the rest of the black community from visiting. (Blacks were allowed on a small part of the beach that was some 10 miles away from his neighborhood.) That led Mason, who would become one of the leading civil rights activists in Mississippi – to plan a “wade-in” as both an act of civil disobedience and a family event. Women, children and teenagers were there “just having a good time,” Jimerson recalls.

At worst, the protesters expected to be ordered off the beach by police, and maybe some arrests. That was what happened in the two previous wade-ins. What they didn’t see coming was a mob of white men armed with clubs, brass knuckles and bricks...READ MORE

Linda Poon is an assistant editor at CityLab covering science and urban technology, including smart cities and climate change. She previously covered global health and development for NPR’s Goats and Soda blog. For more information, visit www.citylab.com.