of the building is made of iron sheet metal. Part of the window frames, the drainpipes and the linings of the eaves on the roof are made of copper sheet metal. The central hall of the station building reaches to the top of the building and is a barrel vaulted space with an area of about 780 square metres. The former waiting halls of the station building are both shield arc vaulted spaces of about 450 square metres in area. The exit halls to the Rautatientori square and to the Eliel Square are 200 and 350 square metres, respectively. The covered inner yard surrounded by the "U" shape of the building has an area of about 1100 square metres. Clock tower The clock tower of the station is among the best known landmarks in Helsinki. At the time of its completion it was the tallest tower in Helsinki, and it soon became a popular vantage point, with entrance tickets sold at its first times. As the station served as a military hospital during World War I, the clock tower was used as a temporary morgue. During World War II, the Lotta Svärd used the tower for air surveillance. The clock tower has vantage terraces in all four cardinal directions. The stairs at the bottom of the tower are made from concrete. The stairs at the top are made from wood. Nowadays the tower is no longer open for the public for security reasons, with the exception of invited guests, such as descendants of Eliel Saarinen. The height of the clock tower measured from the street level is 48.5 metres. At the top of the tower is a globe supported by four winged wheels, symbolising the internationality of the station and the Finnish railways. The tower is built of walled brick and its facade consists of about 3600 pieces of Hanko granite. The roof is made of wood and is covered in copper. The copper roof of the tower weighs about five thousand kilograms and has a total area of about 150 square metres. The diameter of the bottom of the dome at the tower is about 4.5 metres. The area of the granite facade is about 1030 square metres. Each granite stone is about 250 millimetres thick and weighs about 240 kilograms. The clock tower was completed in 1919 but was only fitted with German-made weighted clocks in 1922. At