‘Hell's Gate’ is actually a long, narrow lagoon that could be mistaken for a river. Its banks are a nice place for a picnic lunch on a drive around the north, though swimming and snorkeling are not advised as the water can be murky. Some say the rather dramatic name comes from the water crashing at the mouth of the lagoon; others say it's from the sulfuric pong of rotting seaweed that sometimes builds up here.