Mare Island Shoreline Heritage Preserve at 1595 Railroad Avenue, Vallejo, California.

We went here on a hot weekend in June (high of 100). Beautiful place to walk around. Interesting dynamic and group of people running the place. Everyone is really nice and there's a lot of character.

Watch out for rattlesnakes. When we were there, someone's dog was bitten by a rattlesnake and my wife and I had to rush them down to the bottom of the hill in our car. So keep your pet on a short leash and stay in the middle of the path. Don't let your dog explore or lunge at things.

Wear sunscreen. Use mosquito repellent as well. This is a neat place but just keep in mind, a nature preserves job is to preserve nature so that means there are lots of critters out there. That also means you should be respectful and stay on paths.