2 Mile Long Perfectly Straight Hallway
Wired has a photo gallery on the Stanford Linear Accelerator up, including this photo of a two mile long perfectly straight horizontal shaft that tricks your mind into thinking it slopes upwards because your brain is used to dealing with the curvature of the earth at such distances. My first thought was wondering how far I could throw a frisbee down it. And if it also happened to be like 50 feet tall, it would be fun to shoot arrows (no wind impact at all).
