Datura is a member of the solanaceae family of plants. Grown extensively around the world in temperate and tropical environments, the largest diversity of these exist in the States and Mexico.
Brugmansia is a related version that looks like the angel's trumpet shape of Datura. You can easily identify the difference in the two as the Brugmansia flowers hang straight down and the Datura blooms reach up towards the sun.
Often referred to as moon flowers, Datura comes in a range of colors from pure white to deep purple and yellow. Because of the prickly and globular seed packet its also has the common name of "thorn apple". Highly poisonous, it's best to locate these magnificent and attractive plants at the back of the garden bed or a location that's difficult for curious children and pets to access.
Despite the risks associated with these varieties I find them quite fascinating as they come in single and double forms. The double versions appear to have two trumpets in one bloom, one nestled inside the other.