From the various flavors that have been available to the struggles of unveiling it nationwide, here's what you should know about McD's minty green shake.

McDonald's popular Shamrock Shake typically comes back well ahead of spring, and this year is no exception. Some of the Chicago-based fast food giant's locations have already begun offering the sweet concoction. You just might be able to get your hands on one early -- if your local McDonald's has rolled it out.

Have you ever wondered what gives McDonald's iconic Shamrock Shake that distinct green color? You may not be surprised by the answer.

The Shamrock Shake is a milkshake made with vanilla soft-serve ice cream, artificially flavored minty green syrup and whipped topping. McDonald's debuted the first Shamrock Shake in 1970, and the cult classic has been returning to the menu around St. Patrick's Day each year since.

Shamrock Shakes are back at the restaurants. The Oreo Shamrock McFlurry has made a limited time return, as well. Start the day smarter. Get all the news you need in your inbox each morning. Shamrock Shakes sales do some good.