Mima Mounds Natural Area Preserve in Olympia offers a couple miles of hiking, but its real attraction is its strange bubble-like hills. A natural and scientific curiosity, Mima Mounds’ hill-studded grasslands seems out of place surrounded by evergreen forests and the Capitol SF peaks in the background. Several theories exist as to why the small grass-covered mounds exist. These theories range from the extraordinary, such as the one that gophers made them, to the tame, like the most accepted belief that they were created by glacier deposits. An educational kiosk (and viewing platform) at the beginning of the trails describes these various theories. This Wikipedia page describes some of the theories in greater detail.
Situated adjacent to Capitol State Forest, Mima Mounds offers a great educational experience and family outing. I rank this hiking area high on the family friendly list as it features several picnic areas and easy, flat walking paths. I also think that the area serves families well because of its amenities. In additional to lots of educational signage, the site includes two raised observation platforms (one of them handicapped accessible) that can give you a pretty good vantage point looking westward over the grasslands. If you do visit, bring your sunscreen though – there’s no shade at all on the trails.