Dunalastair (Scottish Gaelic: Dùn Alastair, meaning "fort of Alexander") is an estate in the southern part of the Highlands, in Perthshire, Scotland.[1][2]

There is the ruin of an old baronial-style mansion in the grounds, built in 1862 by General Macdonald, the then-owner of Dunalastair. The original tower house was burnt down after the 1745 rebellion, as the great chieftain Alexander Robertson of Struan was a Jacobite supporter.

The estate is overlooked by the peak of Schiehallion, a conical mountain sometimes translated as "Fairy hill of the Caledonians".

https://en.wikipedia.org/wiki/Dunalastair

Schiehallion has a rich flora, interesting folklore and archaeology, and a unique place in scientific history for an 18th-century experiment in "weighing the Earth".

Schiehallion's isolated position and regular shape led it to be selected by the English astronomer Charles Mason (of Mason–Dixon line fame) for a ground-breaking experiment to estimate the mass of the Earth in 1774.[10] The deflection of a pendulum by the mass of the mountain provided an estimate of the mean density of the Earth, from which its mass and a value for Newton's gravitational constant G could be deduced. Mason turned down a commission to carry out the work, and it was instead coordinated by the Astronomer Royal, Nevil Maskelyne. He was assisted in the task by mathematician Charles Hutton, who devised a graphical system to represent large volumes of surveyed heights, later known as contour lines.[11]

https://en.wikipedia.org/wiki/Schiehallion