Ilana Trachtman was thinking of getting married at a theme park. Well, a former one. Glen Echo Park hadn’t been an amusement park since 1968, but it had transitioned into a cultural destination for families in the wider D.C. area with an aquarium, children’s theaters and the vintage Dentzel carousel from its past life. Trachtman, a Philadelphia-based director, had grown up just a few miles away in Rockville, Maryland, and had “beloved, magical memories of the place.” But as she toured the site with her fiance, a park ranger shared a story she’d never heard about the theme park. It had long turned Black children and their parents away from its rides, and it took over nine weeks of picketing — and a sit-in on the carousel — to end the segregation…