Hook Lighthouse is one of the world’s oldest lighthouses—second only to the Tower of Hercules in Spain. The structure that stands in County Wexford today was built in the 12th century, but local tradition holds that there has been some sort of signal at this site since the 5th century. The tower stands 35 meters tall, and you can climb 115 steps inside its thick walls to the chamber at the top. It’s said that the phrase “by hook or by crook” originated with this lighthouse. When Oliver Cromwell set out to conquer…