What is the world's tallest structure?

Answer 1

it is the burj dubai, it has height of 804 m high

Answer 2

The tallest man-made structure is Burj Dubai, a skyscraper under construction in Dubai that reached 707 m (2,320 ft) in height on September 26, 2008. By 7 April 2008 it had been built higher than the KVLY-TV mast in North Dakota, USA, which is still the tallest completed structure at 628.8 m (2,063 ft). In September it officially surpassed Poland's 646.38 m (2,121 ft) Warsaw radio mast, which stood from 1974 to 1991, to become the tallest structure ever built. Guyed lattice towers such as these masts had held the world height record since 1954.

The CN Tower in Toronto, Ontario, Canada, standing at 553.3 m (1,815 ft), is the world's tallest completed freestanding structure on land. Opened in 1976, it was surpassed in height by the rising Burj Dubai on September 12, 2007.It has the world's second highest public observation deck at 446.5 m (1,465 ft).

The Petronius Platform stands 610 m (2,001 ft) off the sea floor leading some, including Guinness World Records 2007, to claim it as the tallest freestanding structure in the world