According to the sign, Pen Y Garreg is 37m high, 161m long and was built in 1903. It covers 124 acres and holds 6,000,000,000 litres of water. The part that amazes me most is the fact it was built over 100 years ago! Every person who worked on it will be long dead, but it still stands in testament to their hard work and engineering skills. In 1903 it would be very hard work too! Pax kept telling me that any minute a fast jet would scream past at eye level. No such luck. Come on RAF, where are you?