The Monaco Grand Prix differs in several ways from other Grands Prix. The practice session for the race is held on the Thursday preceding the race instead of Friday. This allows the streets to be opened to the public again on Friday. Until the late 1990s the race started at 3:30 p.m. local time – an hour and a half later than other European Formula One races. In recent years the race has fallen in line with the other Formula One races for the convenience of television viewers. Also, earlier the event was traditionally held on the week of Ascension Day. For many years, the numbers of cars admitted to Grands Prix was at the discretion of the race organisers – Monaco had the smallest grids, ostensibly because of its narrow and twisting track. Only 18 cars were permitted to enter the 1975 Monaco Grand Prix, compared to 23 to 26 cars at all other rounds that year.