The first attempt to explore Venus took place less than 4 years after the first ever satellite when the Russians launched Sputnik 7 on the 4th February 1961, however, it failed to leave orbit. This mission was followed by Mariner 1 for the Americans and Sputnik 19 for the Russians, both of which also failed.
The first successful flyby was by Mariner 2 on 27th December 1962 which took atmospheric and magnetic readings.
A number of failed missions followed and it was not until 18 October 1967 that Venera 4 entered the atmosphere, taking samples before it was crushed. Further successful missions followed and on 15th December 1970 Venera 7 succeeded in landing and returned data.
On 20th October 1975 Venera 9 returned the first pictures from the surface and for 2 years from 1978 Pioneer Venus Orbiter radar mapped the surface.
There were several successful orbital and landing missions over the following years and from 1990 to 1994 the Magellan mission took detailed radar images of the surface
The loss of Magellan on 13th October 1994 marked the end of Venus exploration as the dense surface pressures and constant cloud cover meant it was unlikely that more useful data would be returned until such time as technology moves forward.