Yes. Go to Seven Island and head south into the Sevault Canyon. About halfway between the canyon entrance and the Tanoby Ruins you will find a cave called the Tanoby Key.
Inside there are seven boulders and seven floor switches, similar to those on Victory Road. Using Strength, push all seven boulders onto the switches. When you solve this puzzle, there will be a small earthquake.
Step out of the Tanoby Key and head the rest of the way to the Tanoby Ruins. When you enter the chambers after solving the puzzle, the Unown will appear. Each chamber has a certain set of Unown, so search them all.