The link you followed will bring you to this page:

https://www.facebook.com/events/3354969734721240/?acontext=%7B%22event_action_history%22%3A[%7B%22mechanism%22%3A%22calendar_tab_event%22%2C%22surface%22%3A%22bookmark_calendar%22%7D]%2C%22ref_notif_type%22%3Anull%7D