Standing on Southsea Common overlooking the promenade in Portsmouth, Hampshire, is the Portsmouth Naval Memorial. It commemorates nearly 10,000 naval personnel of the First World War and almost 15,000 of the Second World War who were lost or buried at sea. Names of those lost in the Second World War are recorded on panels set into the low walls of an enclosure added to the north, leading to a barrel-vaulted pavilion on each side. The extension was unveiled by the Queen Elizabeth, the Queen Mother, on 29 April 1953. Among those commemorated at Portsmouth are most of the crew of HMS Bulwark, who died in 1914, and 127 men who lost their lives when the mine layer HMS Princess Irene exploded while anchored near Sheerness on 27 May 1915.