Back in June, construction workers in Hidalgo, Mexico were hard at work adding a third lane to the Pachuca-Huejutla highway when they stumbled upon a 1,375-year-old pyramid.

175 years ago on Feb. 2, 1848, the United States and Mexico signed the Treaty of Guadalupe Hidalgo. It ended the Mexican-American War and changed the lives of early Coloradans forever.