This monument is on the Inti Urqu (or Intiorko) plateau, where the Battle of Tacna / Batalla del Alto de la Alianza took place on 26 May 1880. The battle lasted for over 5 hours and was a decisive victory for the Chilean forces over Peruvian and Bolivian troops. The victory ensured Chilean domination of the Tarapacá region and ended the Peru - Bolivia alliance; Bolivia's decimated army took no further part in the War.