Okotoks Erratic, situated 7 km west of Okotoks, Alberta, Canada, is a supreme example of a glacial erratic. Commonly known as Big Rock, this quartzite boulder is the world's largest known glacial erratic at 16,500 metric tons. Matching an erratic back to its parent bedrock can shed light on the route of an ice flow; research suggests that this erratic was transported across hundreds of miles of North American landscape, sometime between 16,000 and 10,000 BCE. More recent in its history, Big Rock may have been used as a landmark for the Blackfoot First Nation. In fact, the phrase 'O'kotok' translates to 'rock' in the Blackfoot language. The site is decorated with countless native pictographs, yet to be deciphered. 