During our Zip Line Days, guests climb a 23-foot tree to our zip platform then proceed to a 487-foot zip line. Purchase one ticket for each time you would like to travel down the zip line. Pre-registration is required. About Heard Natural Science Museum & Wildlife Sanctuary Heard Natural Science Museum & Wildlife Sanctuary is a private 501(c)3 nonprofit organization dedicated to bringing nature and people together to discover, enjoy, experience, restore and preserve our priceless environment. The Heard was founded in 1967 by Bessie Heard at the age of 80. In a time when the rate of expansion of the Metroplex was slower than today, she foresaw the need to preserve a place where future generations could experience nature. Today, the Heard's mission of bringing nature and people together is carried out through education, particularly of young people, which emphasizes an appreciation of nature and its conservation. For more information, visit heardmuseum.org.