Cultivator #6, invented and built by the British, aka, White Rabbit No. 6, was an underground tank developed in the early months of WWII, 1939-1940 and designed to travel across "no-man's-land" in a trench of its own making.

Cultivator No. 6 went by a number of names, all of which disguised its true purpose These were White Rabbit Number Six, Cultivator No. 6, N.L.E Tractors, and Nellie, in reference to the NLE department.
Also, Churchill was known to often refer to the machine as his mole.
The Cultivator No. 6 had two main parts; the head and the body. The head was responsible for actually digging the trench, while the body provided the machine’s movement.

 

Cultivator #6 used two 600 hp Paxman diesel engines. This allowed the digging and automotive systems to have their own dedicated powerplant.

 

The head was a large machine in and of itself, weighing around 30 tons and measuring 30 ft. 6 in. long, 8 ft. 7 in. high and 7 ft. 3 in. wide. It connected to the body via a hinge, allowing it to pivot up and down to ascend or descend.
A large plough blade cut through the upper 2 ft. 6 in. of soil, while a rotating cutting cylinder removed the lower 2 ft. of soil.

 

Fully assembled, the monstrous Cultivator No. 6 was 77 ft. 6 in. long and weighed 130 tons.
The body of the machine was over 45 ft. long and closely resembled a WWI era tank. This section weighed 100 tons. Its 2 ft. wide tracks ran around the entire outside of the vehicle, which had a top seed of 3.04 mph on the surface.

 

At full speed the machine could dig around 0.5 miles of trench in an hour, moving 8,000 tons of soil in the process.
As it went it would cut a trench 5 ft. deep and 7 ft. 6 in. wide. The soil removed from the cut was then deposited along sides of the trench by conveyors on top of the machine. This added another few feet of depth to the trench.
Though the machine showed promise, it would never seen action. From the earliest stages of the war it was clear combat had changed dramatically since WWI. It was not going to be fought in trenches, and as a result, Cultivator No. 6 had no use.
Five are believed to have been built, including the pilot vehicle. However four of these were scrapped soon after war, with the fifth surviving until the 1950s, when it too was scrapped.

Aerial reconnaissance photo of the opposing trenches and no-mans land between Loos-en-Gohelle and Hulluch in Artois, France, taken at 7:15 pm on July 22, 1917. German trenches are on the right and bottom, British trenches are at top left. The vertical line to the left of center indicates the course of a pre-war road or track.