The Infinite Corridor is the hallway, 251 meters (825 feet) long, that runs through the main building of the Massachusetts Institute of Technology. The corridor is important because of the layout of the campus which makes the corridor the most direct route between the residence halls and the classrooms, as well as the main route between east campus and west campus. The corridor is decorated by many bulletin boards and display boxes which have been remarkably unchanged over the years. The center of the corridor (under the Great Dome) contains a wall on which are listed the names of MIT alumni who died in each of several wars.

On two days each year, the sun sets in alignment with the Infinite Corridor. These days occur in late January and mid-November. The MIThenge site (http://web.mit.edu/planning/www/mithenge.html) has more information about this phenomenon, as well as about the Infinite Corridor in general.

During the 1960s, a common Technology Day demonstration used the unobstructed length of the corridor to demonstrate the finite speed of light in a simple, direct way. A strobe light, photocell, and oscilloscope were positioned at one end of the corridor, and a mirror at the other. The round-trip time was about two microseconds. The photocell picked up both the direct and reflected flashes. The flash duration being well under a microsecond, the result was two nicely separated pulses on the oscilloscope screen.