A blood-red sea of ceramic poppies is spilling from the Tower of London to commemorate British and Commonwealth soldiers killed in World War I on the 100th anniversary of its start.

The Duke and Duchess of Cambridge joined Prince Harry on Tuesday to "plant" the ceramic poppies in the dry moat surrounding the Tower to honor the military dead.

The installation, called "Blood Swept Lands And Seas Of Red," is made up of 120,000 ceramic poppies. More will be added in the coming months until there are 888,246 — one for each of the British and Commonwealth soldiers killed in the war.

Gen. Richard Dannatt says one of the installation's virtues is that it allows the dead to be remembered together as well as being individuals.