Embarcadero (San Diego)

Flat and right outside the Convention Center, the bayfront promenade was built for people on foot. It runs north past Seaport Village and Waterfront Park towards the airport and Harbor Island, up to about 7 miles one way, so a 30-minute out-and-back and a long run are equally simple. An optional loop of Harbor Island adds roughly three miles with water on both sides, and the path continues on to Spanish Landing Park for anyone who wants more. Go early if you can: the cobbled stretch around Seaport Village is the busiest on foot.