Hamilton Mausoleum built
1842 CE.
Shown on the map at 55.783°, -4.032°.
The Hamilton Mausoleum is a mausoleum located in Hamilton, South Lanarkshire, Scotland. It was the resting place of the family of the Dukes of Hamilton. The mausoleum is Category A listed. Built in the grounds of the now-demolished Hamilton Palace, its high stone vault holds the record for the longest echo within any man-made structure in the world, taking 15 seconds for the sound of a slammed door to fade. In 2014 the record was thought to have been broken at the Inchindown oil storage tanks in the Scottish Highlands, however this was classed as a reverberation, rather than an echo.
Text from the Wikipedia article Hamilton Mausoleum, licensed CC BY-SA 4.0.