Mark Hamill, Mark Ruffalo, and More Celebrate National Puppy Day

Happy National Puppy Day! March 23rd is a day to celebrate our favorite furry pals, so Twitter is filled with pictures of adorable doggos from people all around the world. From the Marvel Cinematic Universe's Mark Ruffalo to Star Wars' Mark Hamill, the pup content is warming all sorts of hearts today. Even the official accounts for movies like John Wick and shows such as Star Trek are celebrating their four-legged friends.

According to the National Puppy Day website, the holiday was established in 2006 by Colleen Paige, a Celebrity Pet & Home Lifestyle Expert/Author who also started National Dog Day and National Cat Day. National Puppy Day is not only to "celebrate the magic and unconditional love that puppies bring to our lives," but also a "day to help save orphaned puppies across the globe and educate the public about the horrors of puppy mills." You can learn more on Paige's website here.

While there is a serious side to the holiday, there is also the joy of getting to see puppy pictures online. Many fans are bummed that Chris Evans hasn't posted about his dog, Dodger, so here's a little reminder of the fact that Evans spent Valentine's Day with his pup last month.

Evans may not have taken to Twitter today, but plenty of other folks have. Here are some of our favorite dog posts...