The N1 was a super heavy-lift launch vehicle intended to deliver payloads beyond low Earth orbit. The N1 was the Soviet counterpart to the US Saturn V, planned for crewed travel to the Moon and beyond. However, each of the four attempts to launch an N1 failed in flight, with the second attempt resulting in the vehicle crashing back onto its launch pad shortly after liftoff. The project was derailed by the death of its chief designer Sergei Korolev in 1966; the program was suspended in 1974 and canceled in 1976.
It's pretty wild just how much dependence the Soviet space program had on Korolev personally that once he died the whole thing just fell apart. Having one guy driving the technical side and securing the political side is possible if you have a sufficiently talented person (like Korolev) but it's inherently unstable.
That said the Soviets did do a lot of really cool space stuff, including getting probes to land and photograph the surface of Venus (which is an extremely hostile environment).