1. Mecca's Great Mosque Where: Saudi Arabia Completed Year: Unfinished Total Cost: $100+ Billion For almost two millennia, the Great Mosque in Mecca has undergone continuous renovations, with expenses surpassing $100 billion and still increasing. This awe-inspiring structure spans an impressive ninety-nine acres and is designed to host up to four million worshippers simultaneously, offering… Continue reading Prepare to Be Amazed: The World's Most Expensive Construction Marvels Revealed