If only there was a way to get all of those people there and back home without a car.

Look up the largest stadium in the world, Strahov in Prague, that hosted the Communist "Spartakiad" parade every May 1st. Almost every performer and attendee arrived via the high-capacity tram and bus terminal Smyčka Dlabačov, often after taking a train and the metro. As a result, the parking lot is absolutely tiny.