Architecturally gargoyles were designed to take water away from rooftops over to the sides of a building to prevent rainwater from eroding the walls; used before gutters were around.
Gargoyles on churches may have been intended to convey the idea of evil and used to scare people into coming to church by signifying the end times were near. They also may have conveyed that evil was to be kept outside the church.
Other ghoulish figures:
The Bilmore House took six years to complete and was finished in 1895:
It was a great trip even Stella enjoyed it!