1) The world's largest volcano, Mauna Loa in Hawaii, is also one of the most active. It stands over 13,000 feet (4,000 meters) above sea level.

2) The Serengeti National Park, located in Tanzania and extending into Kenya, is renowned for its vast savannahs, diverse wildlife, and the annual wildebeest migration. It is a UNESCO World Heritage site and a popular destination for safari enthusiasts and nature lovers.

3) The Victoria Falls, situated on the Zambezi River between Zambia and Zimbabwe, is one of the largest and most spectacular waterfalls in the world. It is over 1.7 kilometers (1 mile) wide and has a height of 108 meters (354 feet), attracting visitors with its breathtaking beauty and power.

4) The assassination of Archduke Franz Ferdinand of Austria in 1914 triggered the start of World War I.