That lone black dot to the northwest of Santa Fe, New Mexico is where I live. Speaking of nuclear exchanges...
November 1, 1952
United States of America - Elugelap, Enewetak Atoll, Marshall Islands
Operation Ivy - Shot Mike - 10.4 Megatons
First full-scale test of the thermonuclear principle. Using liquid deuterium cooled to cryogenic conditions, this experimental device was 6.19 m (20 ft 3 in.) and weighed approximately 74 metric tons.
November 22, 1955
Union of Soviet Socialist Republics -
Semipalatinsk Test Site, East Kazakhstan Region, Kazakhstan
Test RDS-37 - 1.6 Megatons
This was the first thermonuclear weapon design capable of delivery by aircraft, 6 months before any other nation.
November 8, 1957
United Kingdom of Great Britain and Northern Ireland - Kiritimati (Christmas Island), Kiribati
Operation Grapple X - 1.8 Megatons
The success of this nuclear test of this led to the repair of relations with the United States following the Suez Crisis, culminating with the 1958 US-UK Mutual Defence Agreement.
June 17, 1967
People's Republic of China - Lop Nur Test Base, Xinjiang Uygur Autonomous Region
Test No. 6 - 3.3 Megatons
Shortest period between first successful tests of fission and fusion devices (33 months). Although the USSR played an important role in the PRC's nuclear weapons program prior to the Sino-Soviet split, Test No. 6 was an independent development program.
August 24, 1968
French Republic - Fangatafoa Atoll, French Polynesia
Operation Canopus - 2.6 Megatons
President DeGaulle accelerated French thermonuclear weapons development after the People's Republic of China publicly announced the success of Test No. 6. Approximately 40% of the French Navy (by tonnage) was present to observe and secure the test site.