Located to the east of Everett, in King County, in the U.S. state of Washington, the Old Cascade Tunnel is one of the creepiest locations of America. It’s said to be haunted by the ghosts of the 1910 Wellington disaster.
The tunnel was finished in 1900 for the purpose of removing 8 switchbacks to get over the mountains. It was 2.6 miles long and had a grade of 1.7% (1 in 58.8ft). This tunnel is caving in and it's very dangerous. DO NOT ENTER for any reason. Sadly, the tunnel met most of its demise back in 2006, when the east end collapsed. Water pooled around that end and formed a stagnant lake. In the winter of 2006/2007, the tunnel lining suffered a massive failure about 600 ft. in from the west portal. There is currently a rock and debris dam in the tunnel that completely blocks passage and forms a dam so that there is a small lake (approximately 130,000 cu. ft.) backed up behind the dam. The tunnel lining is cracked and split overhead in the vicinity of the failure. Another failure could happen at any time. The tunnel is extremely dangerous and entry is prohibited. A viewpoint has been constructed at the west end in an area that should be safe if another collapse occurs.
Photo credit: Panoramio.com