Completed and opened in 2014, the 246.8-metre-tall (810 ft) Olympic Park Observation Tower's five circular roofs are meant to evoke the Olympic rings; although it has also been described as "a huge nail". The design of the towers themselves were inspired by blades of grass. It is the sixth tallest observation tower in China and the 22nd highest in the world. Visitors can look out over the park and the entire city of Beijing from all five platforms, ranging from 186 to 243 metres (610 to 797 ft) in height.