Five Weeks in a Balloon: Or, Journeys and Discoveries in Africa by Three Englishmen

Five Weeks in a Balloon, or, A Journey of Discovery by Three Englishmen in Africa is an adventure novel by Jules Verne, published in 1863. It is the first novel in which he perfected the "ingredients" of his later work, skillfully mixing a story line full of adventure and plot twists that keep the reader's interest through passages of technical, geographic, and historic description. The book gives readers a glimpse of the exploration of Africa, which was still not completely known to Europeans of the time, with explorers traveling all over the continent in search of its secrets.

Summary source: Wikipedia: Five Weeks in a Balloon · CC BY-SA 4.0