The Queen of the Night [Silenicerus grandiflora] is a night blooming cactus of the Cereus family, native to the Antilles, the Caribbean, Mexico, throughout Central America, and a few locations in South America. It climbs on trees and on rocks. The blossom lives only for one night. It opens slowly, starting with nightfall. It is full open at and dies with the first light of the new day.
The photo was taken at 10:35 pm. I used a handhold flashlight to illuminate the flower.

Sony DSC-H2, f/2.8, 1/40 sec, ISO 250, bias -0.7, focal length 6 mm, hand holt flashlight.