AKA floripondio, Brugmansia, and in English, Angel's trumpet. This fine example was in the garden of the finca.
I've heard various versions of what happens to those that take a nap anywhere near one of these. Some Guatemalans would have you believe that you will sleep better than ever before, whilst others will note grimly that you are unlikely to ever wake up.
It seems that the whole plant is toxic and in the section titled uses Wikipedia explains that florifundio is "sometimes ingested for recreational or shamanic intoxication as the plant contains the tropane alkaloids scopolamine and atropine; however because the potency of the toxic compounds in the plant is variable, the degree of intoxication is unpredictable and can be fatal."
I first came across these impressive flowers in the beautiful little garden at the back of a house attached to the Arco de Santa Catalina, which belongs to a former ballerina who now runs a dance school. An active promoter of the New Year's Eve Festival in the Calle del Arco, she is also a tireless opponent of the equally noisy activities that go on in the famous old street for most of the rest of the year. Gilda Jolas...como jodas, as they say in certain unrepentantly hedonistic circles in Antigua.