Fill in the gaps with the correct words.

The Kremlin’s crenellated red ... walls and its 20 ... were built at the end of the 15th century. The irregular ... of the Kremlin wall encloses an ... of 27,5 hectares. Its overall length is 2,235 metres. The height ranges from 5 to 19 metres, ... on the terrain. The Spasskaya ... is one of the Kremlin’s 20 towers. It overlooks Red Square. Its ... is 71 metres. The Kremlin Clock is a ... clock on the Spasskaya Tower. The Kremlin clock ... have a diameter of 6,12 metres, and they are placed on all four ... of the Spasskaya Tower.