Conversation so far:
What was Garry Kasparov towards the top of?
He was at the top of the chess world.
When did Garry Kasparov reach the top of the chess world?
Kasparov became the youngest ever undisputed World Chess Champion in 1985 at age 22.
What important matches did Garry Kasparov play to reach the top?
His first win in a superclass-level international tournament was scored at Bugojno, Yugoslavia in 1982.
When did Garry Kasparov start playing chess?
He began playing chess at age 6.
Did Garry Kasparov have any obstacles or difficulties in reaching the top?
Politics threatened to affect his matches while reaching the top.
How did politics prevent Garry Kasparov from playing?
Politics threatened Kasparov's semi-final against Viktor Korchnoi, which was scheduled to be played in Pasadena, California.
What is the most remarkable aspect of Garry Kasparov's rise to the top?
He became the youngest ever world No. 1, a record that lasted 12 years until being broken by Vladimir Kramnik in January 1996.
Did Garry Kasparov beat any other champions to reach the top besides Vladimir Kramnik?
Yes, he defeated Alexander Beliavsky, Vasily Smyslov, and Anatoly Karpov.

Question: What was the biggest or most impressive win he had?
Self-contained rewrite: What was the biggest or most impressive win Garry Kasparov had?