What A Long, Strange Trip It's Been

What A Long, Strange Trip It's Been is an achievement. If you are highly active in all of the seasonal world events — Lunar Festival, Love is in the Air, Noblegarden, Children's Week, Midsummer, Brewfest, Hallow's End, and Winter Veil — you will gain as well as a rare mount, Reins of the Violet Proto-Drake. This achievement takes the longest amount of time to complete, requiring at least a year to complete all of the prerequisites.

A letter from Alexstrasza the Life-Binder
Upon completion, players receive the, attached to a letter from Alexstrasza:

Philosophy
A note about Blizzard's philosophy on holiday achievements: