The Treaty Oak, a giant, at least 500 year old, live oak, is one of the most famous landmarks, and symbols of, Austin. It is located, incongruosly, in one of the most heavilly developed parts of the city, between East Fifth and Sixth Streets in the middle of downtown. It was once part of a larger grove of fourteen ancient live oaks, which the Comanche called the Council Oaks; all of the rest of the grove were destroyed over the course of the development of downtown. The Park Department claims that the Indians venerated Treaty Oak as a "Tree-God", and while this is probably hyperbolic, it is fairly certain from what records remain that the Council Oaks were an important part of their lives.
Treaty Oak supposedly gets its name from Stephen F. Austin signing the first boundary treaties with the local Indians under it, though this almost certainly never happened. It is known that the Council Oaks were very famous within Austin for almost all the city's history, but this didn't stop them from being destroyed, one by one, to make way for the development of downtown. By the 1920s, all of the Council Oaks except Treaty Oak were gone, and a campaign began to keep it too from being cut down, culminating with the American Forestry Association entering it into their hall of fame as "The most perfect example of an American tree" in 1929, and the city finally buying the land Treaty Oak was on to make into a park in 1937.
The most famous incident in Treaty Oak's recent history was its near death by poisoning in 1989. An unstable local man, jilted in love, used massive amounts of Velpar, a herbicide designed for hardwoods, to try and kill the tree and leave his mark on history. He was caught, sentenced to nine years in prison, and a huge, nationally publicized effort, bankrolled by Texas billionaire entrepeneur/genius/kook H. Ross Perot, was made to save the tree. Despite all this, only about a third of the tree survived, and its long-term future is still uncertain. Now, a program is on to collect and germinate its acorns across the state, so that in the event Treaty Oak does die, its line and memory will not.