Steve Jobs has to be on any list of the leaders who radically altered our world in the 21st century. He has also personally undergone a lot of physical stress. The photos below reveal this aspect.

In mid-2004, Jobs announced to his employees that he had been diagnosed with a cancerous tumor in his pancreas.

In early August 2006, Jobs delivered the keynote for Apple's annual Worldwide Developers Conference. His thin appearance and unusually listless delivery raised speculation about his health.

On Dec. 16, 2008, Apple announced that marketing vice-president Phil Schiller would deliver the company's final keynote address at the Macworld Conference and Expo 2009, again reviving questions about Jobs' health

In April 2009, Jobs underwent a liver transplant.

On Jan. 17, 2011, one and a half years after Jobs returned from his liver transplant, Apple announced that he had been granted a medical leave of absence.

Jobs announced his resignation from his role as Apple's CEO on Aug. 24. In the letter, Jobs wrote that he could no longer meet duties and expectations as Apple’s CEO.