After the conquest of Mexico, rumors of golden cities (Quivira and Cbola in North America and El Dorado in South America) motivated several other expeditions. Many of those returned without having found their goal, or finding it much less valuable than was hoped. Indeed, the New World colonies only began to yield a substantial part of the Crown's revenues with the establishment of mines such as that of Potos (Bolivia) and Zacatecas (Mexico) both started in 1546. By the late 16th century, silver from the Americas accounted for one-fifth of Spain's total budget.[5]