Al-Idrisi created the most accurate map of the medieval world for King Roger II of Sicily. It took 15 years to compile and remained the primary reference for travelers for three centuries.

Ottoman Admiral Piri Reis drew a world map that includes the first accurate details of the coast of Brazil and Antarctica (without ice). He compiled it from 20 older maps, including one by Columbus.

Using trigonometry and measuring the dip of the horizon from a mountain in Nandana (Pakistan), Al-Biruni calculated the Earth's circumference as 40,075 km. This is 99.7% accurate to modern values.

Ibn Battuta traveled over 120,000 km—more than Marco Polo. His book, The Rihla, documents the geography, politics, and cultures of lands from West Africa to China with incredible anthropological detail.

He was the first to combine history and geography in a large-scale work, Meadows of Gold. He described the phenomenon of the monsoon winds and the causes of ocean currents.

Muslim sailors perfected the Magnetic Compass and the Kamal (a celestial navigation tool). These inventions allowed them to cross the Indian Ocean and reach China safely, long before European explorers.

His Mu'jam al-Buldan is a massive geographical dictionary. It lists names of towns and cities in alphabetical order, giving their exact coordinates, history, economy, and famous inhabitants.

Al-Maqdisi traveled for 20 years to write The Best Divisions for Knowledge of the Regions. Unlike arm-chair geographers, he only described places he had personally visited, focusing on climate, commerce, and customs.