. . . . "Astronomy allows the building of Copernicus' Observatory, one of the more valuable early Wonders. It is a prerequisite of navigation and theory of gravity."@en . "Astronomy (Civ1)"@en . . . . . . "Astronomy allows the building of Copernicus' Observatory, one of the more valuable early Wonders. It is a prerequisite of navigation and theory of gravity."@en . . .