Fernando Alonso has caused a wave of excitement about the Indy 500, but the event has been influencing motor racing and the car industry for over 100 years. ESPN takes a look at the iconic oval race's best -- and most important -- innovations.
Rear-view mirrors
The first time a rear-view mirror was placed on a racing car was by Ray Harroun at the inaugural Indianapolis 500 in 1911. Harroun did so as a response to criticisms that he had entered a single-seater, rather than a car with space for a co-pilot riding alongside the driver.