In 1950, Bruno Pontecorvo dropped off the face of the earth.

Alright, first things first. Who was Bruno Pontecorvo?

He was a brilliant Italian Jewish physicist. His work with Enrico Fermi led to the discovery of nuclear fission. He also created innovations in the field of oil drilling. And one summer day, while vacationing back in his home country, his whole family disappeared.

They would resurface soon after... in the Soviet Union. Pontecorvo decided to defect.

Why would an accomplished nuclear physicist, with all opportunity seemingly at his fingertips, decide to live in a Stalinist hellhole? Well, he was a lifelong socialist. And, possibly, a Soviet spy.

Pontecorvo ended up living the rest of his life in Russia. Better than dropping off the face of the earth for real?

That's debatable.