If you want to see them run in person.
http://www.lemansclassic.com/language/en/grids/The wife and I attended this year, the next one is in 2020.
In short, the Le Mans Classic is run every other year on the 24 Hours of Le Mans track. It is open to any car that has every competed in the 24 hour race.
Divided into 6 grids; #1) 1923 > 1939 #2) 1949 > 1956 #3) 1957 > 1961 #4) 1962 > 1965 #5) 1966 > 1971 #6) 1972 > 1981 plus Group C, Jaguars and Porsches.
Each grid races three times for ~ 1 hour on Saturday and Sunday (including night sessions) plus practice and qualifing on Friday.
The wife now understands my love of GT 40's and late '60s early '70s front engine Ferrari's.
If you decide to go stay near the train station, the T-1 tramline's last stop going south is inside the track ~15 minute walk to our grandstand. Plus the train station is a good place to buy water, much needed in 95*+ heat. Book early, the hotels sell out a year in advance.