Discovery and exploration of the Solar System that moved through the sky. Although the Greek philosopher Aristarchus of Samos had speculated on a heliocentric reordering of the cosmos, Nicolaus Copernicus in the 16th century developed a mathematically predictive heliocentric system. His 17th-century successors, Galileo Galilei, Johannes Kepler, and Isaac Newton, developed a modern understanding of physics that led to the gradual acceptance of the idea that Earth moves around the Sun and that the planets are governed by the same physical laws that govern Earth. In more recent times, this led to the investigation of geological phenomena such as mountains and craters and seasonal meteorological phenomena such
Paris in the 16th century art, did not come until the very end of the century with the reign of Henry IV. Through the 16th century, there were only four bridges across the Seine, two on each bank, insufficient for the growing city and the amount of traffic they carried. The Paris bridges at the beginning of the 16th century were largely made of wood, and were frequently washed away in floods or knocked down by ice on the frozen river. The most important bridge was the Pont au Change, which had been built in 1304 under Philip le Bel, and was site where the