Exploration of the Moon invention of the telescope, an increasing number of people began to recognise the Moon as a sphere, though many believed that it was "perfectly smooth". In 1609, Galileo Galilei drew one of the first telescopic drawings of the Moon in his book and noted that it was not smooth but had mountains and craters. Later in the 17th century, Giovanni Battista Riccioli and Francesco Maria Grimaldi drew a map of the Moon and gave many craters the names they still have today. On maps, the dark parts of the Moon's surface were called "maria" (singular "mare") or seas, and the
Craters of the Moon National Monument and Preserve to "preserve the unusual and weird volcanic formations". The Craters Inn and several cabins were built in 1927 for the convenience of visitors. The Mission 66 Program initiated construction of today's road system, visitor center, shop, campground and comfort station in 1956 and in 1959 the Craters of the Moon Natural History Association was formed to assist the monument in educational activities. The addition of an island of vegetation completely surrounded by lava known as Carey Kipuka () increased the size of the monument by in 1962. Since then the monument has been enlarged. On October 23, 1970, Congress set