Ka'ba- The Ka'ba is a big stone structure, that lies at the heart of Al Masjid Al Haram. The Ka'ba is the holiest buliding for Muslims. Everyday more than a billion Muslims face it and pray. The Qu'ran states that Prophet Abraham and his son Ishameel were the true founders.
The Ridda Wars, were wars waged by Abu Bakr, the first caliph of Islam, against the Bedouin tribes who renounced their faith in Islam. These Bedouin people renounced their faith after the death of Muhammad, because many of them saw their faith as an allegiance with the prophet himself. Once the prophet died, these Bedouins felt that their allegiance was over, and thus renounced their faith.