I'm not sure how you measure which park in the USA is "the largest urban park". I immediately thought of Forest Park in Portland Oregon, which is larger than an

I'm not sure how you measure which park in the USA is "the largest urban park". I immediately thought of Forest Park in Portland Oregon, which is larger than anything in SF. I found this list of largest city parks: http://www.infoplease.com/ipa/A0933260.html http://www.infoplease.com/ipa/A0933260.html I'm not sure what counts as 'urban' in your definition. Also, redwoods might be the largest trees on earth, but not the largest organisms. And they're not the oldest trees on earth either.