Complex sentence: In 1972, he captured the World Chess Championship from Boris Spassky of the USSR in a match, held in Reykjavík, Iceland, publicized as a Cold War confrontation which attracted more worldwide interest than any chess championship before or since.
Split into simpler sentences: In 1972, he captured the World Chess Championship from Boris Spassky of the USSR in a match that was widely publicized as a Cold War confrontation. The match, held in Reykjavík, Iceland, attracted more worldwide interest and publicity than any chess championship before or since.