October 23 Holidays

Mole Day is celebrated from 6:02 a.m. to 6:02 p.m. on October 23 — the date and time combining to reference Avogadro’s number, 6.022 × 10²³, the number of atoms or molecules in one mole of a substance and one of chemistry’s most fundamental constants. National Boston Cream Pie Day celebrates the custard-filled, chocolate-glazed cake invented at the Hotel Omni Parker House in Boston in 1856 — a creation so beloved in Massachusetts that it was designated the official state dessert in 1996. Hungarian Republic Day marks October 23, 1956, when Hungarian students and workers launched the Hungarian Revolution — a popular uprising against Soviet occupation that was crushed by Soviet tanks within days, and which is also celebrated as the day in 1989 when Hungary formally became a republic. Libya Liberation Day marks October 23, 2011, when Libya’s National Transitional Council declared the country officially liberated following the death of Muammar Gaddafi.