Deep Navigation Colliery Deep Navigation Colliery Deep Navigation Colliery was a coal mine in South Wales, that operated from 1872 until 1991. Located next to the co-developed village of Treharris in the borough of Merthyr Tydfil, on development it was the deepest coalmine in South Wales Coalfield by some . Producing the highest quality steam coal, it powered both the Cunard passenger steamers RMS "Mauretania" and RMS "Lusitania" in their successful attempts at the Blue Riband prize for the most rapid Atlantic Ocean passage. The mine is also thought to have been one of several locally that provided coal to the RMS Titanic;
Sirena Deep Philippine legends of the sirenas, which are a mix of mermaids and sirens. The new name will now appear on geologic and bathymetric maps. Sirena Deep The Sirena Deep was discovered in 1997 by a team of scientists from Hawaii. Its depth (10,732 metres) is thought to be second or third only to the Challenger Deep and possibly Horizon Deep, currently the deepest known places in the ocean. It lies along the Mariana Trench, 200 kilometers to the east of the Challenger Deep and 145 km south of Guam. The Sirena Deep was most probably formed, not through transform fault