<Li> Hamilton Mausoleum, Hamilton, South Lanarkshire, Scotland: Its high stone holds the record for the longest echo in the world, taking 15 seconds for the sound of a slammed door to delay . </Li> <Li> Gol Gumbaz of Bijapur, India: Any whisper, clap or sound gets echoed repeatedly . </Li> <Li> The Golkonda Fort of Hyderabad, India </Li> <Li> The Echo Wall at the Temple of Heaven, Beijing, China </Li>

Name the property which leads to the formation of echo