For 17 years, from 1911 to 1928, Denny Hill Park — Seattle’s first — was 60 feet above its regraded surroundings, then, in the name of progress, it was leveled. Architect Jerry Garcia is proposing that the park be re-built, along with a museum-like pavilion constructed of rammed-earth exterior walls that, amazingly, could be made of dirt from the original Denny Hill