[1] In 2003, Peña became the first Colombian to wear the yellow jersey at the Tour de France.

Peña's 2003 Tour de France, where he served as a domestique for Lance Armstrong, is described in detail in Matt Rendell's book A Significant Other.

He earned his nickname "El Tiburon" ("the shark") due to his looks and the other sport he excelled at besides cycling – swimming.

Peña finished 7th in the 100 meter freestyle Pan American swimming championships for juniors in 1991.

[2] Later, Pena was implicated in the 2012 USADA Reasoned Report into doping on the US Postal team and was concluded to work with Dr. Michele Ferrari and received blood transfusions during his Tour de France participations.