Venera and VeGa

During the Cold War, the Soviet Union created the Venera (Venus in Russian) program. Between 1961 and 1984, 16 iterations of the Venera probe were launched to the planet, but the true number of probes sent will never be known.

Venera 1 and 2 were merely flyby probes and did not enter the planet's atmosphere. Iterations 3-16 did enter the atmosphere, and even made major breakthroughs in space exploration. Venera 3 was the first man-made device to enter the atmosphere of another planet. Venera 7 was the first  to make a soft landing on another planet. Venera 9 was the first to return images from another planet. Venera 13 was the first to record sounds on another planet, and Venera 15 was the first to provide high-resolution radar mapping scans.

In December of 1984, sister crafts called VeGa 1 and 2 were launched to the surface of Venus. Both crafts entered the atmosphere, but VeGa 1 did not successfully land and no data was transmitted. VeGa 2, however, managed to land and transmit data for 52 minutes on the night side of the planet. VeGa 2 marked the last time a spacecraft successfully descended to the surface of Venus.