Bolero

Bolero is a Latin-based genre of music and dance known for its sensuality and intimacy; in fact, it's known to some as the second dance of love -- in addition to the rhumba, of course. But unlike the rhumba, bolero's origins are somewhat unclear and wildly debated. Some say that bolero originated as a Cuban dance that spread quickly to Spain; others say that Spain danced and played a version of the bolero long before Cuba altered the form. According to this idea, the bolero was created in Spain in the 18th century by the dancer and choreographer Sebastien Zezero. The form traveled to Cuba and by the mid-1800s had morphed into an almost entirely different form carrying the same name. The Cuban form of bolero is often thought to be the truest form of bolero, regardless of where it came from, and Pepe Sanchez's 1883 "Tristezas" is considered by some to be the first bolero ever formally written.
But regardless of who created what (and where), the bolero is an important element within both Cuban and Spanish culture, though the form is very different between the two. Cuban bolero is danced and played in 2/4 time and rooted strongly in African percussion. The bolero dance is very focused on couples, and the two dancers remain very close throughout the whole dance. Spanish bolero, on the other hand, is played in 3/4 time with a slightly less rhythmic undertone. The couples dancing Spanish bolero often dance apart (like modern informal fast dancing), only coming completely together at certain parts. Though the Spanish bolero style is still found occasionally, it is the Cuban style that gave birth to the various modern boleros still danced and played today.
Like most foreign music and dance styles, the bolero eventually found its way to the United States in the 1930s and became a sort of craze. As it shifted cultures, however, it underwent a few alterations. The American bolero shares more characteristics with the rhumba than any other traditional style, and it's slightly slower and far more intimate. Additionally, the American bolero was changed from the Cuban-based 2/4 to a slightly more relaxed 4/4.