Many Americans viewed him as a dictator, but in Venezuela, Chavez was a charismatic hero.
Chavez had neither been seen nor heard from, except for photos released in mid-February, since submitting to a fourth round of surgery in Cuba on Dec. 11 for an unspecified cancer in the pelvic area. He was first diagnosed in June 2011. According to the government, Chavez returned home on Feb. 18 and had been confined to the military hospital in Caracas ever since.
Maduro said that Chavez died "after battling a tough illness for nearly two years." In Venezuela, the streets were filled with mourners crying and holding pictures of their provocative and unpredictable leader.
Chavez's rise to power was rocky. Born in an impoverished neighborhood, he joined a military academy and began pushing for social reform. The self-described champion of the poor first tried to overturn Venezuela's powerful elites in a failed 1992 coup.
After two years in prison, Chavez went from soldier to politician, winning the 1998 presidential election, with huge support from the country's poor.
"He's a man that cared about us" one Venezuelan woman said as she cried. "He did not give anything to me, but he gave it to my people."
Chavez ran Venezuela for more than 14 years as a virtual one-man show, with all state institutions under his personal control. During his presidency, Chavez was very critical of the U.S. He objected to the wars in Iraq and Afghanistan, and during a United Nations speech, even referred to former President George W. Bush as "the devil."
But Chavez also saw his fair share of protests, strikes and coup attempts. He used his country's oil to form connections with world powers and developed relationships with Iran and Cuba.
Campaigning had already begun to replace Chavez as president. The opposition previously said it would contest the government's candidate in a snap election that it argues should have been called after Chavez was unable to be sworn in on Jan. 10 as the constitution stipulates.
Chavez has said Maduro should succeed him. Maduro has frequently commandeered all broadcast channels, Chavez-style, to tout the "revolution" and vilify the opposition.
Under Venezuela's constitution, the national assembly chief would take over as interim president. The constitution also says that elections should be called in 30 days.
The Associated Press contributed to this report.