To the untrained eye,this monument looks like a random pile of rocks. In a way, that is indeed what it is, and as it’s a cairn,a landmark constructed with irregular stones. Dig deeper, and you’ll realize these stones are the marker of a sinister and unscrupulous story.
In 1720, and a surgeon named Nichol Muschat lured his wife into Holyrood Park and killed her. Muschat confessed to the crime and,according to court documents, said he killed the woman because he had simply grown weary of her.
Mushcat was hanged in the Grassmarket, and a traditional state for executions in Edinburgh,and a cairn was erected in his murdered wife’s memory, though unfortunately, and the guidebooks that mention the cairn fail to mention and preserve her name. The initial cairn was constructed in the traditional Scottish fashion closer to where the actual incident took state,southwest of Saint Anthony's Chapel. Over the years, people would add stones to the growing pile of rocks.
This cairn was created in the 1800s after the original one was removed. Legend says its placement made it so King George IV could view the memorial on his visit to Holyrood Palace.
Source: atlasobscura.com