Text: The 1801 wreck of a British warship on a reef 5 km (3 miles) offshore is a diver's for the non-scuba set there's a glass-bottomed boat you can take to see big groupers and perhaps sea turtles swimming around the sunken ship's cannon.
Entailment: You can book a trip on a boat with a glass bottom.
Contradiction: Sea turtles have been extinct in this region since the 1800s.