Constructed in 1930 by the Civilian Conservation Corps, 125 limestone stairs lead to the top of a former toboggan run at Swallow Cliff North. Although the runs were closed in 2004, the stairs remain a popular exercise destination for fitness buffs and casual walkers. (Some stair climbers build pebble piles at the top of the stairs to keep track of their trips up and down.)During the winter, the bluff still serves as an active sledding hill. Visitors provide their own sleds. (Learn more about sledding in the forest preserves.) The stairs are cleared and salted. Hikers and trail runners can access the brown and yellow trails via a short connector trail from the top of the stairway. The full yellow loop is roughly eight miles, extending west to Cap Sauers Holding Nature Preserve and east to Palos Park Preserve. Hikers can cut the loop in half by using the white connector trail to cut back to Swallow Cliff North. These trails are part of the Sag Valley unpaved trail system, which is open to hiking, biking, horseback riding and cross-country skiing. Swallow Cliff Woods South has small and large open-air shelters with picnic tables for family gatherings and special events. Groups of 25 or more must purchase a permit; otherwise, they are available on a first-come, first-served basis. Trail users can access the yellow trail at the Swallow Cliff South entrance as well. For a 4.75-mile loop, head west on the yellow trail.