Tunnel vision

Please do not take the title literally; this is not about applying extreme vignetting in order to simulate loss of peripheral vision. What I want you to share is your pictures of tunnels (and of what is or is not happening inside/around them). Photos can be taken from within or outside a tunnel, but please let the tunnel be a significant part of your picture's theme, not just a barely visible dot at the background. Since the definition of a tunnel is not universally agreed upon, (and as much as I dislike disqualifying people's photos) I reserve the right to disqualify entries that I feel do not meet the criteria (for instance I will not accept simulated tunnels (as in extreme vignetting or other post-processing techniques), single-standing arches (although a series of adjacent arches producing a tunnel effect could be accepted), or hallways in residential buildings).