Look at the historical map of California shown below. Historical maps from different time periods can tell us what people thought about the world at different points in time. Old maps can provide us with useful information on which parts of the world had been explored when each map was made.
Source: Library of Congress.
Many Spanish explorers came to North America in the 1500s. They were called conquistadors and were looking for gold and new lands. In 1535, some Spanish explorers reached what they thought was an island in the Pacific Ocean. They named it California. They probably named it after an island full of gold and pearls described in a Spanish novel. By 1540, explorers had discovered that the southern part of California was a peninsula. More than 100 years later, however, it was still common for cartographers to draw California as an island. A Dutch cartographer named Joan Vinckeboons made this map, probably around 1650. He drew it with an ink pen and watercolors. He colored areas of land green on the map.