Prophet Muhammad destroys all the idols in the Kaaba with Imam Ali's help and washes the images that had been drawn inside.
He then introduced Islam to the Meccans, discarding their ideas of nationalism and tribalism, and offered a general amnesty regardless of if they convert to Islam.
Prophet Muhammad told Bilal to climb on top of the Kaaba to give the Azaan. Ikrima bin Abu Jahl saw that and made disparraging remarks about it, with a couple other pagans agreeing. They were soon shokced when Prophet Muhammad came over and said "I know what you said about Bilal" and repeated their words verbatim, revealing his miraculous knowledge.
The Prophet stayed in Mecca for 19 more days and during that time many prominent Meccans who had initially resisted conversion would end up converting instead of fleeing, including Ikrimah bin Abu Jahl, Suhayl ibn Amr, and Safwan ibn Umayyah.
Lecture notes available at http://www.why-quran.org/?p=691.
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