A Requiem Mass was celebrated for Kennedy at the Cathedral of St. Matthew the Apostle on November 25, 1963. Afterwards, Kennedy was interred in a small plot, 20 by 30 ft., in Arlington National Cemetery. Over a period of three years (1964–1966), an estimated 16 million people visited his grave. On March 14, 1967, Kennedy's remains were disinterred and moved only a few feet away to a permanent burial plot and memorial. It was from this memorial that the graves of both Robert and Ted Kennedy were modeled.