Blood Swept Lands and Seas of Red was a public art installation created in the moat of the Tower of London, England, between July and November 2014. It commemorated the centenary of the outbreak of World War I and consisted of 888,246 ceramic red poppies, each intended to represent one British or Colonial serviceman killed in the War. The ceramic artist was Paul Cummins, with conceptual design by the stage designer Tom Piper. The work's title was taken from the first line of a poem by an unknown soldier in World War I.

The centenary of the outbreak of World War I was commemorated in late July and early August 2014. Governments in Europe held a series of official commemorative events to mark the occasion.