In 1492, Columbus landed in today's Dominican Republic, believing he had reached Asia.
He was the first European to discover the Americas.
This discovery marked a huge turning point for the Spanish, who went on the colonise the Americas and become the most powerful kingdom in Europe.
Around 1510, the Spanish founded the first settlement in Central America and discovered the Isthmus of Panama, a land passage connecting the Atlantic and Pacific, which could facilitate the movement of trade and people.
A few years later they conquered the Aztec and Inca Empires.
California remained untouched by the Europeans for many years, separated from the Europeans by mountains, jungles and deserts.
The closest European port to California was Acapulco, which actively traded with the Philippines (also a Spanish colony).
Massive galleons, called the Manila galleons, sailed back and forth from America to the Philippines, over several months, carrying spices and porcelain in exchange for gold.
The Spanish were keen to find a faster route connecting America to Asia.
A popular thought was that there might be a passage to the North - so a navigator, Cabrillo, sailed off to explore, reaching as far as Point Reyes and missing the San Francisco Bay because of the fog.
There are many references to him across the state, including schools and the Cabrillo Highway.
A replica of his ship was built in San Diego in 2015.