Here, ahead of a regional summit in Havana this week, are some of the region’s most influential leaders on both the left and right ends of the political spectrum.

(Alejandro Ernesto/AFP/Getty Images)

Cuba: Raúl Castro

Born: June 3, 1931

Took office: Feb. 24, 2008

Since taking over from his brother Fidel in 2006, Raúl, 82, has instituted a series of market-driven changes, allowing Cubans to start small businesses, buy and sell their homes and own cars without special permission.

(Jorge Silva/Reuters)

Venezuela: Nicolás Maduro

Born: Nov. 23, 1962

Took office: April 19, 2013

The handpicked successor of Hugo Chávez, who died last March. Chávez pushed through radical economic and political changes during his 14-year rule, and Maduro is now struggling to carry forward his socialist vision.

(Matilde Campodonico/AP)

Uruguay: José “Pepe” Mujica

Born: May 20, 1935

Took office: March 1, 2010

A former Tupamaro guerrilla who spent 14 years in a military prison during the 1970s and ’80s, Mujica has become the Pope Francis of Latin American presidents. His candor and conspicuously spartan lifestyle have made him a widely popular figure in the region. His government legalized marijuana last year.

(Jose Jacome)

Ecuador: Rafael Correa

Born: April 6, 1963

Took office: Jan. 15, 2007

Correa is among the leftist Latin American populists who have steered their countries away from U.S. influence and plowed his nation’s resource wealth into social programs. His approval ratings are among the highest in the region.

(LEO LA VALLE/AFP/Getty Images)

Argentina: Cristina Fernández de Kirchner

Born: Feb. 19, 1953

Took office: Dec. 10, 2007

Fernández won reelection by a huge margin in 2011, but her popularity has slumped along with Argentina’s sputtering economy.

(Steffen Schmidt)

Brazil: Dilma Rousseff

Born: Dec. 14, 1947

Take office: Jan. 1, 2011

A former Marxist guerrilla jailed by the military dictatorship in the 1970s, Rousseff was handpicked by her predecessor, Brazil’s charismatic president Luiz Inacio Lula da Silva. Her popularity has recovered since the huge protests her government faced last year.

(Claudio Reyes)

Chile: Michelle Bachelet (incoming)

Born: Sept. 29, 1951

Scheduled to take office: March 11, 2014

Bachelet, whose father was murdered by former dictator Gen. Augusto Pinochet and who was tortured herself as a young activist, returns to the presidency after a landslide victory in November. A moderate, she’s under pressure to push Latin America’s top economy further left.

(Ruben Sprich)

Colombia: Juan Manuel Santos

Born: Aug. 10, 1951

Took office: Aug. 7, 2010

Santos was Colombia’s defense chief under his conservative predecessor Álvaro Uribe, and remains a key U.S. ally in Latin America. He’s moved toward the center during his tenure in office, engaging in peace talks with FARC guerrillas. He’s running for re-election in May.

(Laurent Gilleron)

Mexico: Enrique Peña Nieto

Born: July 20, 1966

Took office: Dec. 1, 2012

Peña Nieto has returned the long-ruling Institutional Revolutionary Party (PRI) to Mexico’s presidency after a 12-year absence, and during his first year he’s implemented many pro-business policies that were once associated with the right.

(Enrique Castro-Mendivil /Reuters)

Peru : Ollanta Humala

Born: June 27, 1962

Took office: July 28, 2011

A former army officer, Humala has assuaged worries that he’d take Peru on a radical turn to the left. The economy has sizzled during his presidency thanks to a mining boom, and he’s backing the United States’ push for a Pacific Rim free trade agreement.