Andrea Casiraghi, the 28 year old eldest child of Princess Caroline, is engaged to marry his longtime girlfriend, Tatiana Santo Domingo, also 28. Tatiana, an heiress born in the U.S., comes from prominent Colombian and Brazilian families, her late father and grandfather having been very wealthy. No details of the wedding have been released. Andrea is Princess Caroline’s son from her second husband, Stefano Casiraghi, who died in a speedboat crash in 1990. Andrea Casiraghi is the nephew of Monaco’s Prince Albert II and grandson of the late Princess Grace of Monaco. Photos by Bauer Griffin and Corbis.