The magical Olympic National Park is no secret destination. Visitor centers and their constituent short trail systems are packed during the summer. However, if you hike or backpack deeper into the park you will quickly leave behind the crowds and find yourself in an old growth forest that has remained largely unsullied for millennia. I particularly recommend the Hoh Rainforest trail that hugs the river. This stretch of forest is simply enchanting. I've seen bobcats, Roosevelt elk, black bears, river otters, and blue grouse all in a single day. Consider visiting the Olympics during the peak salmon runs. There is a late Coho run in the winter that serves as the last big feeding frenzy of the year, and this makes for exceptional wildlife spotting.