Sandstorm By James Rollins

An inexplicable explosion rocks the antiquities collection of a London museum, setting off alarms in clandestine organizations around the world. 
And now the search for answers is leading Lady Kara Kensington; her friend Safia al-Maaz, the gallery's brilliant and beautiful curator; and their guide, the international adventurer Omaha Dunn, into a world they never dreamed existed: a lost city buried beneath the Arabian desert. 
But others are being drawn there as well, some with dark and sinister purposes. And the many perils of a death-defying trek deep into the savage heart of the Arabian Peninsula pale before the nightmare waiting to be unearthed at journey's end: an ageless and awesome power that could create a utopia... or destroy everything humankind has built over countless millennia.