The Silent Star (Der schweigende Stern, 1960)
Released in the US as a cut-down, badly dubbed version called First Spaceship on Venus (which you might remember from an episode of MST3K).
This is actually, however, an East German film from the Soviet days. It concerns an international crew of astronauts in the then-near future (the 1980s!), who set out to the planet Venus when Earth scientists discover artifacts from a crashed Venusian spacecraft.
Upon landing, however, the crew finds that Venus is totally deserted.... though there is evidence of a powerful civilization, and its machinery still works.
The original German cut is a very interesting film, as much for the portrayal of the crew as for the still-impressive visual effects.
The international makeup of the crew (German, Soviet, Chinese and Japanese, Indian and African--and co-ed, to boot!) clearly reflects the optimistic brighter side of Soviet ideology. In that respect, it's leaps and bounds ahead of Forbidden Planet, and very much an anticipation of Gene Roddenberry's Star Trek, just a few years later.
Surprisingly for Soviet propaganda, one of the crew is an American. But then again, he was one of those who worked on the atomic bomb--which is mentioned frequently so as to get as many jabs in as possible against the capitalist menace.
(In the American dub, however, all of the Soviet scientists became Westerners, and the American became a Russian. The references to the atom bomb were cut--which also deprived the film of some important character moments.)
The film was adapted from The Astronauts, an early novel by famed Polish SF author Stanislaw Lem. Lem grew to dislike the novel in later years--with the unfortunate result that there is no English translation available.
The DVD of the original cut of The Silent Star is currently quite expensive, so try to get it from a library if you're on a budget. But it's probably better not to watch First Spaceship on Venus until you've seen the film in its proper form.
4 Venusian skulls out of 5.