Bermuda Triangle is a location located off U.S. East Coast that's best known as a place of the supernatural and mystery. The location emmates very powerful magnetic energies that crash and undones human technology and most magic.
Due to the strong magnetic forces of the Triangle, ships and airplanes are known to crash here. Also, Wizards' and most likely other magical creatures powers doesn't work here. But in the episode where Alex reunites Donny and Lucy she wears a colourful pair of shorts to reverse the polarity of the Bermuda Triangle to get in and out.