There are three mountains in the world that could boast to be the highest on earth. Obviously, Mount Everest (8850 m), which I summitted in 2016, is one of them, being the highest point above sea level. However, the Ecuadorian vulcano Chimborazo (6310 m) is the point furthest from the center of the earth and you cannot get ‘closer to the universe’ than on the summit of this peak. Then there is Hawai’i-an vulcano Mauna Kea (4207 m), which is with 10210 m the tallest single mountain on the globe (although the majority of it is below sea level).
Last summer, I climbed a number of Ecuadorian vulcanos with my daughter and summitted Chimborazo on 10 July 2018. More recently, I hiked up Mauna Kea with my oldest sun and we summitted 23 November 2018. So, regardless the way you define the highest mountain, I’ve climbed it 🙂