Deeply conservative and closed to tourists until just a few years ago, Saudi Arabia is undergoing breakneck change as it banks its post-oil fortunes on tourism, investing billions on resorts, airports and infrastructure. While its reforms are not without critics, today's visitors will see a modernizing society living alongside the traditional Saudi values that have preserved it as a prime Islamic pilgrimage destination. Its treasures are many -- from the ancient Nabataean city of Hegra near Al-Ula to the UNESCO-protected town of At-Turaif and mountain village of Rijal Almaa. On the Red Sea coast, the rising sci-fi city of Neom is already opening luxury resorts, with plenty more coming soon.