St. Isaac’s Cathedral is an outstanding monument of Russian architecture of the 19th century and one of the greatest dome constructions in the world, smaller in size only in comparison with the Cathedral of St. Peter in Rome, St. Paul’s Cathedral in London and Santa Maria del Fiore Cathedral in Florence. The interior is richly decorated with paintings belonging to the brush of the leading Russian artists, mosaics so intricate that you can hardly tell them from a painting, exquisite combinations of semiprecious stones, gilded sculptures and bronze bas-reliefs. You can find 14 types of colored Italian marble in the decoration of the interior. The columns of the main icon-stand are made of malachite and lapis-lazuli. Apart from the luxurious decoration, the Cathedral is also famous for its unique engineering design. During the guided tour learn how, using the engineering techniques of the 18th century the builders managed to strengthen the basement of a building so huge! If you are willing to take beautiful pictures and are adventurous enough to go on a climb of 226 steps (no elevator) you can also go up to the Colonnade of the Cathedral. After a breathtaking climb you will be rewarded with a breathtaking view of the city from the height of 43 meters, with the whole panorama of St. Petersburg lying in front of your eyes.