Wikipedia
Cochliasanthus caracalla is a leguminous vine from the family Fabaceae, originating in tropical South America and Central America. The species is named caracalla, a corruption of the Portuguese caracol, meaning snail. This perennial vine (when grown in a climate without frost) has fragrant flowers said to be reminiscent of hyacinths - with a distinctive curled shape, giving rise to the common names corkscrew vine, snail vine, snail creeper, snailflower or snail bean. It is the only member of the genus Cochliasanthus and was formerly considered to belong to the genus Vigna.
This vine is hardy in zones 9 and above, liking full sun and consistently damp soil. It prefers high heat and humidity. In colder zones, it does well in a pot if it is overwintered inside.
Thomas Jefferson called this plant "the most beautiful bean in the world".