By 330 B.C.E., Alexander the Great had reached the pinnacle of success. Or so it seemed. He had defeated the Persian ruler Darius III and seized the capital city of Persepolis. He was determined to continue heading east to Afghanistan in search of his ultimate goal: to reach the end of the world. Alexander’s unrelenting desire to press on resulted in a perilous seven-year journey through the unknown eastern borderlands of the Persian empire that would test the great conqueror’s physical and mental limits. He faced challenges from the natural world, moving through deadly monsoons and extreme temperatures; from a rotating cast of well-matched adversaries, who conspired against him at every turn; and even from his own men. This incredible sweep of time, culminating with his death in 323 BC at the age of 32, would come to determine Alexander’s legacy and shape the empire he left behind.