13 fascinating facts you didn't know about Glen Canyon

Glen Canyon is a rare example of a canyon in an urban setting, and offers a unique escape from the hustle of city life. What started as a eucalyptus grove, turned into a dynamite factory and later an amusement park before becoming the untouched canyon it is today. The term “unparalleled” is used and abused too often, but it works here when describing San Francisco’s little canyon.

Here are a dozen things you might not know about it:

1. The park got its start in the 1850s, when local land tycoon Adolph Sutro purchased 76 acres to plant blue gum eucalyptus trees, giving it the name “Gum Tree Ranch.”
2. In 1868 the canyon was home to the Giant Powder Company, the first commercial manufacturing of dynamite in the US. The plant was apparently located near the present recreation center, at the southern end of the park. An explosion at the factory on November 26, 1869, killed two and injured nine others, essentially destroying the factory complex.
3. In 1889, the Crocker Real Estate Company bought the canyon to develop a neighborhood. Real estate developers Baldwin and Howell installed an amusement park and zoo, with hot-air balloon rides and tightrope walkers who performed on a wire stretched across the canyon.
4. The zoo was to contain a massive building designed by prolific local architect Frank S. Van Trees (of 3800 Washington fame), but plans were downsized. Instead they built Morro Castle, a Moorish-style castle that resembled the famous structure of the same name in Havana, Cuba. It was likely located somewhere near today’s Sussex Street between Mizpah and Conrad Streets.
5. After the 1906 earthquake and fire, displaced refugees lived in hundreds of temporary earthquake shacks constructed in the canyon mouth and on open ground between houses.
6. From 1907-1922, Glen Canyon Park operated as a picnic ground for adults. Crocker Real Estate put in tables and benches. According to SF Parks Alliance, “It was fenced and rented to organizations for company picnics that often turned into boisterous drinking brawls.”
7. When neighbors got worried about development in the canyon, the city bought the 101-acre Glen Canyon Park and Recreation site in 1922.
8. The recreation center was constructed under the WPA (Works Progress Administration) in 1937.
9. The park contains Islais Creek, one of the few remaining free-flowing creeks in San Francisco. The creek supports a diverse streamside ecosystem of willow trees, horsetails, seep monkey flower, and red columbine.
10. Plans to widen O’Shaughnessy Boulevard and make it part of the freeway system in the 1970s were defeated by community opposition led by a group of local women known as the Gum Tree Ladies.
11. The park is home to many critters, including skunks, opossums, raccoons, red-tailed hawks, red-shouldered hawks, great horned owls, coyotes, and the native San Francisco forktail damselfly.
12. Easy social media win: The midcentury homes on concrete stilts in Diamond Heights make for a jarring sight while trekking the Glen Canyon hiking trail.
13. At the end of one of the narrow hiking trails is a hidden rope swing.