ROCKFORD, Ill. (WTVO) — Tensions between Russia and the West over the war in Ukraine have raised the specter of nuclear war for the first time in a generation, and anxious Americans may be wondering if they would survive a nuclear attack on the homeland.

The atomic bomb was developed in part by J. Robert Oppenheimer, an American theoretical physicist who participated in the Manhattan Project, which created the first-ever nuclear weapons that effectively ended World War II.

A nuclear warhead can yield a blast equating to hundreds of kilotons of TNT, killing anyone directly in the blast radius.

According to researchers from the University of Nicosia in Cyprus, if a nuke were to be detonated in a modern city, some people in the surrounding areas could make it if they happened to be in a thick concrete structure, like a bank or subway.

But radiation exposure, which could extend tens of miles from the epicenter could be lethal to those many miles away, resulting in death, starvation, radiation poisoning, and third-degree burns.

Columbia University’s Irwin Redlener, who specializes in disaster preparedness, told Business Insider that America’s enemies would likely target six cities — New York, Chicago, Houston, Los Angeles, San Francisco, and Washington D.C.

According to British defense expert General Sir Richard Barrons, the warhead on an intercontinental ballistic missile has a yield of between 300 and 800 kilotons.

Nuclear weapons historian Alex Wellerstein created NUKEMap, an interactive tool that allows users to simulate a nuclear explosion at any point on a map and observe the fallout.

The damage radius also varies based on whether the nuclear device is detonated in the air or on the ground.

Using the NUKEMap tool, a theoretical surface detonation of a Topol (SS-25) warhead with an 800 kiloton yield on the city of Chicago would kill 504,330 people and injure another 430,000, with a fallout extending as far as 222 miles northeast, to Meredith, Michigan.

The blast radius from the city center would extend to Uptown in the north, Oak Park in the west, and Becks Park in the south.

According to the Federation of American Scientists, the U.S. possesses about 5,500 nuclear weapons, while Russia has about 6,000.

Both Russia and the U.S. possess low-yield nuclear warheads, which have 5-10 kilotons of yield and are smaller than the 15-kiloton bomb dropped on Hiroshima.

However, Russia’s “Tsar Bomba” is the largest ever tested, has a 100-megaton yield.

Experts say the use of nuclear weapons in combat is unlikely, experts say, as it would alienate Russia’s allies and its own people, but world leaders are taking the threats seriously, according to Insider.