A reveler performs during the Carnival parade at the Sambadrome in Rio de Janeiro, Brazil. Carnival, better known in the U.S. as Mardi Gras, is the traditional period of revelry that precedes Ash Wednesday and Lent, a time of sacrifice and penance that prepares the Church for Easter. Lent began on Feb. 10 and concludes with the Sacred Triduum of Holy Week. Easter Sunday is March 27.