11 (of 50). Cathedral Basilica of Saint Louis, St Louis, Missouri

©Jeffrey Isaac Greenberg 12+/Alamy Stock Photo

Often referred to as the New Cathedral to distinguish it from the original church that was destroyed by fire in 1849, this dazzling cathedral incorporates elements of both Gothic and Byzantine architecture. One of its most striking features is the two massive bell towers that rise 210 feet above ground. If that wasn't enough to impress you, the interior is even more awe-inspiring with a grand nave that features more than 40 million pieces of colored glass in its mosaic ceiling.