The Nevada National Security Site (N2S2), previously the Nevada Test Site (NTS) or Nevada Proving Grounds, is a United States Department of Energy reservation located in southeastern Nye County, Nevada, about 65 miles northwest of the city of Las Vegas
Most of the Nuclear test footage on the internet was filmed at N2S2. The craters from the nuclear blasts are still visible, and can be viewed on Google Maps (click picture):
The largest crater, at the north end of the test site, is from the Storax Sedan explosion (1962). The Storax Sedan crater is nearly a quarter mile across and 300ft deep, and was a part of Operation Plowshare, a program to investigate the use of nuclear weapons for mining, cratering and other civilian purposes. The Sedan device was 104 kilotons.
Here is some footage of the Sedan event:
Here is a picture of the preparations for an underground nuclear test in the N2S2. The cables are being placed to measure data.
Here is an arial view of the site:
This is a shot from the first nuclear test at the site:
The following video documents the Upshot-Knothole Grable test, Where an experimental 280 MM Nuclear artillery round was tested.
Operation Plumbbob (1957)