All modern airports have control towers. Control Towers are a vital components of airports. Without them, airplanes are not able to land or takeoff. If airports did not have Control Towers, pilots would have to use their instincts to take off and land the planes, which will eventually cause havoc as pilots will have no communications with each other.

However, there is an exception to the above statement. A non-towered airport is an airport with no operating tower, or air traffic control unit. The vast majority of the world's airports are non-towered, and even airports with control towers may operate as non-towered during off-hours, typically during the night. At non-towered airports, instead of receiving instructions from a tower controller, pilots follow recommended procedures. The exact procedures vary from country to country, but they often involve standard arrival and departure patterns, and they may also include radio calls over a common frequency, such as a Common Traffic Advisory Frequency in the United States, Canada, and Australia.

Non-towered airports are usually small and/or private airports belonging to a single person or company. There is not [yet] a complete list of fully non-towered airports as many airports switch to non-tower mode at off times.

Example of an Non-Towered Airport:

Sedona Airport

IATA: SDX

ICAO: KSEZ

FAA LID: SEZ

Owned by : Yavapai County

Location: Sedona, Arizona, USA

Source: http://en.wikipedia.org/wiki/Sedona_Airport