1973. The reason given for denial of the visa was that he had been given access, at some point in his career, to information vital to Soviet national security and could not now be allowed to leave. After becoming a refusenik, Sharansky became a human rights activist, working as a translator for dissident and nuclear physicist Andrei Sakharov, and spokesman for the Moscow Helsinki Group and a leader for the rights of refuseniks. On 15 March 1977 Sharansky was arrested by the KGB, then headed by Yuri Andropov, on multiple charges, including high treason and spying for several Americans. The accusation stated that he passed to the West lists of over 1,300 refuseniks, many of whom were denied exit visas because of their knowledge of state secrets, which resulted in a publication by Robert C. Toth, "Russ Indirectly Reveal 'State Secrets': Clues in Denials of Jewish Visas". High treason carried the death penalty. The following year, in 1978, he was sentenced to 13 years of forced labor. Sharansky spent time in Moscow's Lefortovo Prison, followed by Vladimir and Chistopol prisons, where for part of the time he was placed in solitary confinement. His health deteriorated, to the point of endangering his life. Later he was detained in Perm 35, a post-Stalin-Gulag-type so-called "strict regimen colony" in Perm Oblast. During his imprisonment, he embarked on hunger strikes to protest confiscation of his mail, and he was force-fed at least 35 times, which he describes as "a sort of torture". Sharansky later opposed force-feeding of Palestinian detainees. Sharansky appeared in a March 1990 edition of National Geographic magazine. The article, "Last Days of the Gulag" by Mike Edwards, profiles through photographs and text one of the few remaining Soviet prison labor camps. The article featured a photo of Natan Sharansky and his wife Avital in their home in Israel viewing photos of the same Gulag where he had been imprisoned, but as it appeared in 1990. Sharansky remarked in the article that after viewing images of the prisoner's faces, he could discern that the protocol of oppression was still at work. The author also showed Sharansky a photo of the cold isolation cell where he had himself been confined. Sharansky commented with irony that conditions had improved slightly: the stark cell now featured a thin bench bolted to the middle of the floor. He said that if that bench had existed when