OK, so I'll incur the wrath of many Americans and say that the 24 Heures du Mans is the worlds most famous motor race. The Indy 500 comes close but Le Mans is just ... special.
The official circuit name is Circuit de la Sarthe. Le Mans refers to the nearby town - the original race took place on the road between Le Mans, Arnage and Mulsanne. The circuit has gradually changed over the years - the current circuit is CIRCUIT N° 16!
The 1st race was held in 1923 and the 1st dominant manufacturer was Bentley with 5 wins up until 1930 when they withdrew, saying that they'd learnt enough about speed and reliability. When the race resumed after WWII in 1949, Ferrari became the dominant manufacturer, challenged in turn by Aston-Martin, Jaguar and Mercedes - Until the 1960's.
In 1955, a major crash caused large fragments of debris (like most of a car!) to fly into the crowd, killing 83 spectators and French driver Pierre Bouillin (who raced under the name Pierre Levegh) and injuring nearly 180 more. It was the most catastrophic crash in motorsport history, and it prompted Mercedes-Benz to retire from motor racing until 1989. Switzerland banned motor racing completely and it was only in 2018 that motor racing returned there for the ePrix of Zurich. Levegh very nearly won the 1952 race single-handed - he had a 4 lap lead with an hour to go when the car's engine failed.
The period from 1964 to 1975 was probably Le Man's golden age. 1st Ford arrived to (eventually) successfully beat Ferrari. Amazingly, 1965 was the last time Ferrari won the overall race - they had 9 wins in 27 years until then. In the late 1960's Porsche began to challenge for overall victories with the fearsome 917 and won for the 1st time in 1970 - the 1st of 19 wins over the next 3 decades.
In 2000, Audi began a winning streak which saw them win 13 times in the next 15 years - and one of those "defeats" was by Bentley which was an Audi with different bodywork (Bentley, and Audi, are owned by the VW group).
During that period, Danish driver Tom Kristensen won 9 times - including 6 in a row between 2000 and 2005 to become "Mr Le Mans". Notice that one of those wins was in a "Bentley" - that's how integrated the effort was - Audi's top driver drove for Bentley!
Majors Le Mans 24 Winners
2018 LMP1: Grizzly Motorsport
2018 LMP2: Torque Freak Racing
2018 GTE: Torque Freak Racing