From the glittering palaces of Riyadh to 10 mansions on London's billionaires' row, this is one royal family with a staggering monopoly on the world's most expensive real estate.

Saudi Gazette reportRIYADH — Riyadh will host the 26th General Assembly of the United Nations World Tourism Organization (UNWTO) from November 7 to 11, coinciding with the organization’s 50th ...