A tank is a heavily armed and armored fighting vehicle that moves on two endless metal chains that are called tracks intended as a primary offensive weapon in front-line ground combat. Most modern tank designs are a balance between heavy firepower, strong armor, and good mobility. Tanks are essentially weapon platforms that make the weapons mounted on them more effective through their mobility and the protection the tank armor provides for the crew. Tanks are usually equipped with a cannon mounted in the revolving turret as well as lighter automatic weapons. The British developed tanks during WW I to fill the need for an armored vehicle that could cross muddy terrain and trenches. A toy custom progress bar for YouTube with LOL Tank.