There is a spot out in Western Nebraska where you can stand in one spot and be in 3 states at once.
Out in the middle of a field southwest of Kimball, Nebraska is a marker. It's actually located on private property, but thankfully the landowner is gracious and allows travelers to visit the tri-state monument up close. It's where Nebraska, Colorado and Wyoming all meet.
This particular point is special in that it actually changed Nebraska's border. When U.S. Astronomer and Surveyor Oliver N. Chaffee marked the spot where the three states meet in 1896, he placed it several hundred feet from where the border was intended to be.
Rather than correct the error, the border was re-drawn to match Chaffee's demarcation. The marker takes on a whole new level of significance when you consider the fact that it effectively moved Nebraska's border. The main monument, the white stone obelisk, has been in place since 1896.