The Object 279 heavy track tank was a unique design which featured a 4-track running gear system. The tank was designed to travel over extremely rough terrain which neither the medium nor light tanks could handle.

The semi-automatic XM25 CDTE grenade launcher is a multiple-shot, airburst weapon system for attacking targets which are out of view. As of early 2017, the future of the XM25 CDTE grenade launcher became uncertain.

Also known as the Armed Robotic Combat Vehicle (ARCV), the Black Knight is very similar in appearance to a tank. It is designed for use in situations deemed too dangers for manned vehicles.

Several countries tried to design a flying tank before the Soviet Union came up with its Antonov A-40 in 1942. Only one prototype (fitted with gliders) was made, but as with other attempts, its armor and armament made it simply too heavy for safe flight.

The Tortuga (Spanish for “tortoise”) is referred to as a half-track or semi-truck vehicle. Only seven Tortugas were built before production was scrapped. By most accounts, the Tortugas were treacherously dangerous to maneuver both in the day and at night.

This cruise missile is being developed for both the U.S. Navy and Air Force. Aerospace and defense company Lockheed Martin manufactures it. It is officially known as a Long-Range Anti-Ship Missile (LRASM).

The Wijnman Koekblikje armored car was a project of the Dutch Army in the 1930s. The “Koekblikje” in its name translates to “jar of biscuits” or “cookie tin.”

This vertical take-off and landing (VTOL) aircraft was developed by a Boeing-owned company for the US military. The Aurora XV-24 LightningStrike is designed to be remotely operated, with a weight of over 5,000 pounds and a cruising speed of over 340 miles per hour.

The possible development of this weapon system was made known when Wired magazine got access to leaked unclassified military documents. The Precision Airborne Standoff Directed Energy Weapon was meant to be used as a kind of “long-range blowtorch”.

The PHASR rifle is a type of dazzler – a weapon meant to cause temporary blindness by use of intense bright light. It is a non-lethal weapon whose effects are not intended to cause permanent damage.

Germany made two prototypes of the Leichter Kampfwagen II light combat car close to the end of the First World War. There were plans to put over 500 of the vehicles into production, but the war ended before any could be made.

The Boeing YAL-1 Airborne Laser Testbed was developed as a kind of super weapon. Mounted on the front of a Boeing wide-body airliner, it was meant to shoot down ballistic missiles even before they exited the airspace of the country which fired them.

The Tsar Tank is one of the strangest-looking armored fighting vehicles ever built. Technically, it was not a tank, since it was not a tracked vehicle, but it was designed (as most tanks are) to travel over very rough terrain.

Production of prototypes of the Heckler & Koch Universal Combat Pistol (HK UCP) began in 2003. By 2009, when the project was canceled, it still had not got past the prototype stage.

Although the word “Maus” in its name translates to “mouse,” there was nothing tiny about the Panzer VIII Maus super heavy tank. It holds the distinction of being the world’s heaviest fully enclosed armored fighting vehicle.

The design process for the German-made Heckler & Koch G11 assault rifle spanned three decades. Tests for the G11 were successful, and there were plans to put it into production, but these were halted by the German reunification and never revived.

Germany developed the K-Wagen super-heavy tank during World War One. It was nearly 10 feet tall, 43 feet long and 20 feet wide. Although the Germany Army was hoping to have a total of ten of these delivered, by the end of the war, there were only two incomplete prototypes.

As far as railway guns go, Germany is well-noted to have built some of the largest, including the Schwerer Dora railway gun. It was developed in the 1930s and slated for use against Stalingrad, in the Soviet Union in World War Two. It did not see any action, however, before being destroyed by Germany at the end of the war.

Development of this automatic shotgun took place in the 1980s. Meant for engagement at close quarters, the Heckler & Koch HK CAWS (Close Assault Weapon System) was designed as an ambidextrous gun. It offered equal ease of use for both left-handed and right-handed shooters.

The XF-85 Goblin parasite lifter was conceived during the Cold War era, following World War Two. The idea was for the mighty B-36 Peacemaker bomber to carry the lightweight Goblin into battle and retrieve it when necessary.

The Focke-Wulf Triebflügel interceptor aircraft was designed to be a vertical take-off and landing (VTOL) tailsitter aircraft. No complete model was built by Germany before the Second World War ended. A Triebflügel is featured in the Marvel Cinematic Universe film "Captain America: The First Avenger (2011)."

The Heckler & Koch HK36 was a West German experimental assault rifle designed in the 1970s. The HK36 did not meet the standards for use by the military, but its design influenced those of later assault rifles.

The BigDog military robot is described by its creators, Boston Dynamics, as the “first advanced rough terrain robot.” It was designed in 2005 but did not progress to military service due, in part, to the amount of noise it generated.

Very little is known about the German Kugelpanzer (or ball tank). Some speculate that it was a scouting vehicle given to Japan by Germany. It was captured by the Red Army of the Soviet Union at the end of World War Two.

Soviet engineers designed this laser pistol in the 1980s for cosmonauts to disable the sensors of enemy spacecraft. Just two prototypes of the Soviet laser pistol are known to still exist.

Before it was canceled in 1965, the Soviet-built LK-1 manned lunar flyby spacecraft was intended to transport a pair of cosmonauts into orbit around the Earth. Plans for the LK-1 were scrapped, and the development of the Soyuz 7K-L1 spacecraft pursued instead.

The Rolls-Royce Thrust Measuring Rig was also known as the Flying Bedstead thanks to its huge, hulking appearance. It was an experimental vertical take-off and landing vehicle developed in the UK in the 1950s. A similar-looking 1960s craft, NASA’s Lunar Landing Research Vehicle, was also called the Flying Bedstead.

This gigantic World War Two German “kanone” was is one of the largest rifled weapons ever built. The Schwerer Gustav was tested against the Soviet Union in the Battle of Sevastopol. The Germans destroyed it at the end of the Second World War.

This double-barreled cannon was designed and built in 1862 during the American Civil War. The unique weapon was never used in battle and today serves as a monument and landmark in Athens, Georgia.

The Highball was one in a series of bouncing bombs developed by the British in World War Two. It was never used in battle, however, unlike the Upkeep bouncing bomb that saw action with the famous Dambusters.

The Avrocar was developed in Canada and intended for use by the US Air Force and Army. This 1950s flying saucer was designed to be capable of vertical take-off and landing (VTOL).

Also known as the Demonstrator, the Tactical High Energy Laser was a prototype chemical laser under development by the US and Israel. The project, which included the use of a large mirror to direct the laser’s beam, was canceled in 2005.

Dubbed the Caspian Sea Monster by Americans, this 1960s Soviet behemoth was actually called the “korabl-maket” or “mock ship.” The Caspian Sea Monster is an experimental vehicle, with movement somewhat similar to a hovercraft. Unlike a hovercraft, however, it does not make contact with the water but floats just above the water surface on a cushion of air.

The purpose of the 1K17 Szhatie self-propelled laser vehicle was to use an intense laser beam to disable enemy vehicles and missiles. The project was developed in the 1970s and 1980s but was canceled with the breakup of the Soviet Union.

The Integrated Sensor is Structure (ISIS) airship from the United States Air Force (USAF) was meant to track and engage both ground-based and airborne targets. The unmanned airship was intended to remain at an altitude of 65,000 feet for up to 10 years.