CARTAGENA, Colombia  The Champagne flowed. Cigar smoke floated in the thick air of the tropical night. Women in miniskirts and men in pressed guayaberas danced at Jet-Set magazine’s fete in this city’s Naval Museum, as the candidates for Miss Colombia sashayed about, flashing perfect smiles and impossibly high cheekbones.

Another party unfolded the same night last month outside Cartagena’s stone ramparts. In a slum called Boston, Ivonne Palencia, an elegant 19-year-old, tiptoed in the mud outside her family’s hovel. Amid the din of firecrackers and reggaetón music, neighbors toasted her victory as Miss Independence, the queen of this city’s slums, with beer.

“We have our queen,” said a glowing Patricia Álvarez, 44, a social worker in Boston who led a collection drive to support Ms. Palencia’s candidacy. “They have theirs.”

Despite making strides in stabilizing the economy in the last decade, Colombia has South America’s most unequal distribution of wealth, except for small Paraguay, according to the Center for Economic Development Studies in Bogotá. And each November this port city puts that inequality on open display, when it hosts two beauty pageants at the same time. The rival contests offer views not only of the country’s yawning income gap but of issues of race and class in a country that has, by some measures, the Spanish-speaking world’s largest black population.