December 13th is National Horse Day, a holiday that was established by Congress in 2004. National Horse Day celebrates this country's rich history with horses—both as workers and companions. Today, there are approximately 9.2 million horses in the United States and millions of people who enjoy their company. We've curated 20 of our favorite horse tattoos across all styles and color palettes to celebrate this day, take a look at the fantastic ink in the gallery below and let us know your thoughts on this story in the comments section.