Source: War Thunder. Official channel.
During the 1960s, global powers started using second-generation MBTs. But as soon as the first M60s, Leopards and T-62s rolled off the factory floor, engineers of the world started working on improved tanks for the next decade. The USSR was the first to complete this task: their T-64 was cleared for production by the mid 1960s. Meanwhile, the US and Germany poured resources into their joint program known as “MBT-70”. It was supported up until 1970, but later cancelled due to costs and differences in requirements.