You probably know them better as the 1906 Olympic Games, but by either name, they ran from the 22nd of April to the 2nd of May. The medals awarded at the event aren’t recognised by the IOC as Olympic medals.
The stadium in Athens.
Here’s what Wikipedia had to say:
The Intercalated Olympic Games were to be a series of International Olympic Games half-way between what is now known as the Games of the Olympiad. This proposed series of games, intercalated in the Olympic Games cycle, was to always be held in Athens, and were to have equal status with the international games. However, the only such games were held in 1906.
The finish of the marathon.
The marathon was won by a Canadian named Billy Sherring, and Prince George ran with him on the final lap.
848 men and six women competed. Four athletes from Australia participated.