They can be launched from surface ships or submarines
The United States has fired 59 fired Tomahawk missiles into Syria in retaliation for the regime of Bashar al-Assad using nerve agents.
The missiles were launched from US Navy ships in the eastern Mediterranean.
The attack is in retaliation for the use of banned chemical agents in an attack on Idlib province on April 4th.
The Tomahawk Land Attack Missile - or TLAM - is an all-weather, long range, subsonic cruise missile.
It is used for land attacks and can be launched from surface ships or submarines.
It can carry a nuclear or conventional payload.
The land-attack version comes with a 1,000-pound-class warhead, called TLAM-C.
It also contains a time-of-arrival control and navigation using Digital Scene Matching Area Correlator (DSMAC) and Global Positioning System (GPS).
The US Department of Defence says this can "significantly reduce mission-planning time and increase navigation and terminal accuracy".
The latest version of the Tomahawk, Block IV, offers two-way satellite communications to reprogram the missile in-flight, and missile health and status messages during the flight.
It also has he ability to provide damage indication in a target area, giving a single-frame image of the target or other areas along its flight path.
Tomahawks are designed to fly at extremely low altitudes at high subsonic speeds.
Constructed in Tucson, Arizona the missiles cost around US$569,000 (€534,880) per unit.
They are 18 feet 3 inches (5.56 metres) in length - though if they have a booster attached, this can increase to 20 feet 6 inches (6.25 metres).
It has a wingspan of 8 feet 9 inches (2.67m) and a weight of around 2,900 pounds (1,315.44 kg).
The Tomahawk can reach subsonic speeds of about 880 km/h.
Their first operational use was in Operation Desert Storm in 1991. The missile has been used in several other conflicts since.
In 1995, the British and US governments signed a Foreign Military Sales Agreement for the acquisition of 65 missiles.
This marked the first sale of Tomahawk to a foreign country.