Tunnel Falls, US

Located between Hood River (Oregon) and Portland (Oregon) in the Columbia River Gorge a small trail leads up a gorge into to the mountains. The trail (Eagle Creek Trail) offers amazing views of waterfalls. The trail has a total length of over 40 km, but at around 7 km into the gorge the diligent hiker is rewarded with a walk through a tunnel which leads right behind the waterfall in the photo above.