The World's Longest Tunnel

In the town of Graniteville, a mysterious Tunnel shows up one day. The Mayor of the town, decides to use it as a tourist attraction. People come from different places to see it. At one point, though, people start to go missing. Also, some time after that, a group of friends (one of which heard about the Tunnel, wanted to visit it, and asked his friends if they wanted to come along) decide to explore the Tunnel and have some unexpected things happen (such as being teleported back to the beginning of it, when they get to a certain area, without realizing it. At least, not at first.) 

The short story is 97 pages long, and has a structure inspired by House of Leaves. Also, the preview photo is from the pdf version of the story.