Surveyor Program

Surveyor (from NASA program) was a robotic spacecraft program to the surface of the Moon. It was the first U.S. mission to make a soft landing on the Moon.  5 missions, including the first one, succeeded. Surveyor 2 crashed at high velocity and Surveyor 4 lost contact, so probably exploded.  All of the other spacecraft are still on the Moon. None of them was planned to return to Earth. Some part of Surveyor 3 were return to Earth by Apollo 12, which landed in 1969. 

source: wikipedia

On the picture of Moon you can see nicely landing spots of all mission with the particular numbers: Luna (red triangles), Apollo (green triangles), and Surveyor (yellow triangles).

The primary goal was to demonstrate soft landings on the lunar surface, to prepare it for Apollo program (Apollo Program), and to test the lunar soil, because it was not known how deep the dust on the Moon was before this mission.

Surveyor 1 was launched on May 30, 1966. It has made soft landing, 4 months after Luna 9 probe(Luna program) and took data about lunar surface needed for the Apollo program.

Surveyor 2 was launched on September 20, 1966 and crashed near Copernicus crater. 

Surveyor 3 was launched on April 17, 1967. It took soil sample of lunar surface and made sample pictures. Apollo 12 used it as a landing target and crew took a picture of the probe and some piece were taken back to Earth.

Surveyor 4 was launched on July 14, 1967 and crashed on Sinus Medii. The contact was lost 2.5 minutes before assumed touchdown. 

Surveyor  5 was launched on September 8, 1967. The mission experienced a helium leakage that could result in failure. However improvised landing allowed the spacecraft to land on the surface. It contained miniature laboratory onboard.  

Surveyor  6 was launched on November 7, 1967. The successful completion of this mission was essential for the Apollo program.  

Surveyor  7 was launched on January 7, 1968 and the mission was final spacecraft of the series. After some operations it suffered battery damage during the first lunar night and transmission contact was rather sporadic. It was planned to be visited by cancelled Apollo 20 mission (cancelled due to Skylab station and also due to subsequent budget cuts).