Mecca is the most holy city in Islam and is considered the first place created on Earth. It contains the Ka'ba, a rectangular building made of bricks that is the centre of Islam. Around 200 million pilgrims attend the Hajj in Mecca every year. St Paul's Cathedral in London contains few treasures after many were lost or stolen over the years. Westminster Abbey was built by Edward the Confessor and serves as the burial place for British monarchs and memorials for famous figures. It continues religious services and remains an important place of worship in London.