Date Dec 11 - 12 2031 Time All Day International Mountain Day Dec 11 (A/RES/57/245) https://www.un.org/en/observances/mountain-day http://www.un.org/en/ga/search/view_doc.asp?symbol=A/RES/57/245 Share This Story, Choose Your Platform! Share this event + Add to Google Calendar + iCal / Outlook export
