The Warsaw Radio Mast (Polish: Maszt radiowy w Konstantynowie) was a radio mast located near Gąbin, Poland, and the world's tallest structure at 646.38 metres (2,120.7 ft) from 1974 until its collapse on 8 August 1991. Designed by Jan Polak, and one of the last radio masts built under Soviet rule, the mast was conceived for height and ability to broadcast the "propaganda of the successes" to remote areas such as Antarctica. It was the third tallest structure ever built, being surpassed as the tallest by the Burj Khalifa tower in the United Arab Emirates in 2009 and Merdeka 118 tower in Malaysia in 2022.Designed by Jan Polak, its construction started in July 1970, was completed on 18 May 1974, and its transmitter entered regular service on 22 July of that year. The opening of the mast was met with extensive celebration and news coverage by the Polish Film Chronicle. The tower was used by Warsaw Radio-Television (Centrum Radiowo-Telewizyjne) for longwave radio broadcasting on a frequency of AM-LW (long wave) 227 kHz before 1 February 1988 and 225 kHz afterwards. Its base was 115.2 metres (378 ft) above sea level. Because a voltage of 120 kV existed between the mast and ground, it stood on a 2-metre (6.6 ft)-high insulator. It operated as a mast radiator (half-wave radiator), so its height was chosen in order to function as a half-wavelength antenna at its broadcasting frequency. The signals from its 2 MW transmitters could be received across essentially the entire globe. The Warsaw Radio Mast's weight was debated; Polish sources claimed 420 tonnes (930,000 lb).The mast was designed for national pride, mainly because of the height of the mast, which made it the tallest structure in the world, surpassing the KVLY-TV mast in Blanchard, North Dakota. It was also designed to broadcast the "propaganda of the successes." However, an unintended effect of the mast's height was that the "officially non-existent Poles of the east" could tune in to Polish radio broadcasts, including those in remote places such as Antarctica. The mast was so powerful that the waves of Polish Radio Programme 1 were received in areas far from the Polish mainland such as Canada and the United States.