[1] 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.

[3] 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.

The monolithic, plinth-based construction prevented structural cracking however, and, after many anxious years, the building settled back to near vertical (180 degrees).

The interior has one of the longest-lasting echoes in the world, a phenomenon dramatically demonstrated to visitors by slamming the entrance doors.

In the early 21st century, the mausoleum had begun to deteriorate and a charitable trust was formed to preserve it (along with the adjacent keepers lodge).