Short answers, pulled from the story.
Mecca lies in the Hejazi region of western Saudi Arabia, set in a narrow valley 277 meters above sea level. It sits about 70 kilometers inland from the Red Sea port city of Jeddah and serves as the capital of Mecca Province.
Mecca is considered the birthplace of Islam and of the prophet Muhammad, who was born there in 570. It holds the Great Mosque and the Kaaba, the direction of prayer for all Muslims worldwide, and is the center of the Hajj pilgrimage, one of Islam's Five Pillars.
Non-Muslims are not permitted to enter Mecca under Saudi law, and using fraudulent documents to do so may result in arrest and prosecution. The first recorded non-Muslim to enter was Ludovico di Varthema of Bologna in 1503, and Richard Francis Burton famously made the pilgrimage in disguise in 1853.
Mecca was most recently conquered during the Saudi conquest of Hejaz by Ibn Saud and his allies in 1925, following the Capture of Mecca in 1924 that overthrew the Sharif of Mecca. The city was then incorporated into Saudi Arabia.
On the 20th of November 1979, two hundred armed dissidents led by Juhayman al-Otaybi seized the Grand Mosque and took tens of thousands of pilgrims hostage. The siege lasted two weeks and resulted in several hundred deaths and significant damage to the shrine, especially the Safa and Marwa gallery.
It has been estimated that since 1985 about 95% of Mecca's historic buildings, most over a thousand years old, have been demolished. Fewer than 20 structures remain that date back to the time of Muhammad, with many sites cleared for hotels and pilgrim infrastructure.