I saw it several times when visiting Chile. It grows in a largish bush. The flowers are large, elongated, white hanging trumpets with some points along the edge of the trumpet that curl back upwards.
I think it is somewhat revered there as a national symbol. I've received gifts and souvenirs decorated with paintings of it.
I have searched on the Internet with every combination I can think of, and can't find it. I'd love to identify it and, ultimately, to get a few specimens. I don't know if it will survive here (Zone 5), but it was growing in the mountains in Chile, which can get kinda chilly, too. I'd especially love to find some to surprise my sister with a gift. (She's in North Carolina, where it has a better chance of surviving.) She spent many years in Chile, and I think it might warm her heart.
Yes, Brugmansia. They're not hardy in the north though. Without a greenhouse you can keep them in a cool basement during the winter in a semi dormant state. They will get bigger each year when handled this way. They are becoming fairly common in my area, I've seen them at alot of local nurseries.
I forgot to add, lapageria rosea as mentioned by Mary is the national flower of Chile. It is a twiner and is mostly found in reddish or pinkish shades although there is a less common white form. It has long bell like flowers that hang downward. It requires a cool temperate climate (not cold) such as what you might find in the pacific northwest. It is difficult to grow and and even more difficult to almost impossible to find plants. Thompson & Morgan used to sell seeds. However, I do believe you are speaking of the more common and easier to grow Brugmansia which is also a South American native.