At San Francisco airport we have hired a car and drove up north to see Redwood National Park. This park is home of the world's tallest trees and protects nearly half of the remaining old growth redwoods. We had a short 5 km hike in the park and saw the Big Tree, a 1500 years old, 115 m high giant. I was really amazing to see these huge trees close up and smell the forest. The trail was surprisingly deserted; I guess this park is still a hidden gem.