St. Mary's Church
For a better look at Alexander Nevsky Cathedral, go up the tower of St. Mary's Church, which is directly across the onion-domed Orthodox church. The church itself is impressive to sit inside, where its walls are covered with old coat of arms from the Middle Ages, making it look like a jacket covered in pins. It's the oldest church in all of mainland Estonia, where it was built by the Danes in the 13th century. Now you can climb up to its tower and take a beautiful photo of the cathedral across the way.