The National Building Museum’s new indoor beach may be making headlines, but it’s not D.C.’s first seashore. For a period of time between 1918 and 1925, Washingtonians dipped into the Tidal Basin to experience some summertime heat relief. Now I know what you’re thinking: you couldn’t pay me to swim in that water today. But with a serious lack of public pools, and no air conditioning, citizens back then were pretty desperate.