Dalkey Island lies less than 300 meters off the south Dublin coastline near the village of Dalkey. This 22-acre island has been occupied for 6000 years and has stunning views in all directions. There are remains of an Iron Age promontory fort, a 7th-century church named after St.Begnet and a Martello tower and gun battery built in the early 1800s. The Vikings used the island as a base around 800 a.d and this may have been one of the busiest ports in the country at that time. The channel between the island and the mainland is very deep, has strong tidal currents and is treacherous for swimming. It has recently been discovered that this area may not only be rich in pop stars and entrepreneurs but may also have rich oil deposits off the coastline. There are also many sea birds, pods of bottlenose dolphins, and a colony of seals.