Mountain Day is a traditional student celebration in which classes are cancelled without prior notice, and the student body heads to the mountains or a park.
The day chosen is often a beautiful, crisp day when the fall foliage is in full color. Mountain Day is most commonly observed at educational institutions in the Northeastern U.S.
International Mountain Day, held each year on 11 December, was established by the UN General Assembly in 2003. The UN encourages events to be organized at all levels that day on behalf of sustainable development in mountains.