What is the setting at the beginning of the story?

The story opens with a conversation between two men—Whitney and Rainsford. They are traveling on a boat and discussing an infamous island that should be somewhere nearby, Ship-Trap Island. Whitney explains to Rainsford that the island is known as a place of dread. Rainsford tries to find the island through the thick, leafy jungle but is unable to spot it. Whitney remarks on the depth of darkness in the region of the Caribbean that they are sailing through. Whitney reveals that the ship is headed to Rio de Janiero in Brazil, and should arrive in a few days.