Greenlake is a park in the middle of Seattle. Glaciers that created Puget Sound also carved the depression for Greenlake 50,000 years ago. It has been filled with water ever since.

The park has two diving board docks set off from the shore. During summer, people dive, jump, fall, flip, flop, and chicken-out on the high boards. Lifeguards patrol the waters with red swimming suits and white, hard-brimmed hats.

People on the diving board dock seem happy. Many hover in that zone between fear and excitement and risk. They walk to the edge and let go for a second.