The Argonath, also called the Pillars of Kings or the Gates of Argonath. Construction was ordered in TA 1248 by Romendacil the 2nd to commemorate his victory against the Easterlings and to use as a marker of the Gondorian northern border. Standing either side of the River Anduin, over time and the reduction of the Gondorian realm, it is no longer actually in Gondor. The large stone monument in the books depicts Isildur and Anarion, however in the films this is changed to Elendil and Isildur.
Trivia-in Sindarin ‘Argonath’ means Royal Stones.