When the shuttle bus lets you off in Old San Juan in the middle of a scorching hot day, you need to take a second to regroup. Cronopios book store (255 Calle de San Jose) is the perfect place to sit for a minute, whip out your tourist map, and figure out what to do. In the back of the store is a patio like area with tables, a fountain, and powerful fans. 🙂
As for what a cronopio is…we turn to wikepedia.