The Scotland community, founded by formerly enslaved people in Potomac in the 1870s and 1880s, hosts its second Juneteenth Heritage Festival with events in Cabin John Park and Cabin John Village, including a parade, a classic car show, a talent show, a Children’s Caribbean Carnival, history lectures, a 5K race, a baseball game and a food court, capped by a fireworks show. 8 a.m. to 10 p.m. Free.