1) The world's largest volcano, Mauna Loa in Hawaii, is also one of the most active.

2) The Sydney Opera House, situated in Sydney, Australia, is an iconic architectural masterpiece and a UNESCO World Heritage site. Its unique design, resembling sailboats or shells, has made it one of the most recognized and photographed landmarks in the world.

3) The world's largest desert is the Sahara Desert in Africa, covering an area of about 3.6 million square miles (9.4 million square kilometers).

4) The first commercial GPS (Global Positioning System) was launched in 1989 and provided accurate positioning and navigation capabilities to users worldwide.