 As the neared Mount Vernon, the world's biggest naval gun, The Peacemaker that was being demonstrated exploded, killing Gardiner and six others.Funeral services for the five white victims were held in the East Room of the White House.Gardiner was interred in the Public Vault at the Congressional Cemetery in Washington, D.C. His remains were later moved to the Gardiner family plot at the South End Cemetery in East Hampton, New York.