Arc de Triomphe
From the Super Mario Wiki
The Arc de Triomphe is a monument in Paris appearing in the game Mario is Missing!. Beneath the Arc, there is the so-called Tomb of the Unknown Soldier. The Eternal Flame burning there was stolen by Koopa Troopas during the events of the game, and it was Luigi's task to get it back and deliver it to the arch. Upon success he was rewarded a prize of 1,750 dollars.
Pamphlet information from Mario is Missing!
The Arc de Triomphe (Arch of Triumph) was built by the architect, Chalgrin, on the orders of Napoleon. It honored the French Empire and the triumph of the French armies during the Revolution. Napoleon died before the structure could be completed in 1836. A small museum inside the arch commemorates both the history of the great general and the building itself. In 1920 the arch became the sight [sic] of the Tomb of the Unknown Soldier. Every evening at 18:30 a delegation from the Old Soldiers Association rekindles the tomb's torch.