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

2) Michael Phelps, an American swimmer, has won a total of 28 Olympic medals, including 23 gold medals, making him the most decorated Olympian of all time.

3) The Alps, located in Europe, are a popular destination for skiing, mountaineering, and hiking.

4) The Mariana Trench in the western Pacific Ocean is the deepest part of the world's oceans, reaching a depth of approximately 36,070 feet (10,994 meters).