AGE 29: Mark Zuckerberg

CEO of Facebook

What makes him powerful: He's built the largest social network ever, with over 1 billion users, and from WhatsApp to Oculus VR, Zuckerberg has overseen a number of huge Facebook acquisitions in the past year. Now the Zuck has the ear of the White House: He recently took a trip to Washington after calling President Obama to express "frustration over the damage the government is creating for all of our future." He was subsequently invited to chat with other tech powerfuls about privacy and intelligence in technology.

Another powerful 29-year-old: LeBron James took the NBA championship and was named the NBA and Finals MVP for the second year in a row.