The Hook Lighthouse is a building situated on Hook Head at the tip of the Hook Peninsula. It is one of the oldest lighthouses in the world and the second oldest operating lighthouse in the world, after the Tower of Hercules in Spain. It marks the eastern entrance to Waterford Harbour. The current structure has stood for almost 800 years. The existing tower dates from the 12th century, though tradition states that Dubhán, a missionary to the Wexford area, established a form of beacon as early as the 5th century. The tower was built by Strongbow's son-in-law William Marshall, Earl of Pembroke, who succeeded Strongbow as Lord of Leinster. The exact year of construction is not known, but Pembroke first came to the region in 1201 and the first map that shows the lighthouse serving its function is dated 1240, so construction must have taken place between these dates.
In 2001 the lighthouse was opened to the public as a tourist attraction after the old keepers houses were turned into a visitor centre.In June 2011 the structure was placed first in a Lonely Planet piece listing the "Top 10 Flashiest Lighthouses"; the author described Hook as "The great granddaddy of lighthouses".