What is the main setting in the novel, Dinosaur Summer?

Dinosaur Summer has four major settings: Gluck's circus, a freighter, a river in Venezuela, and El Grande—the plateau of the lost world. Much of the novel's suspense derives from the anticipation it generates in the reader for the delayed appearance of El Grande. Circus Lothar whets the appetite for adventure by presenting the dinosaurs and then depicting a frightening show in which the venator Dagger threatens to break out of its cage.