moat
dry or watery ditch surrounding a fortification or town
city moat
city moat, dry or filled with water
Nor Loch
reservoir in City of Edinburgh, Scotland, UK, drained in 1820
city grade offset
defensive measure
anti-tank trench
ditches dug to hold up the advance of enemy tanks
Birmingham Manor House
moated building that formed the seat of the Lord of the Manor of Birmingham, England
Slender West Lake
ecological and historic district of Yangzhou, Jiangsu, China, preserving various Qing-era landmarks centered around some of the town's former canals and moats
Forbidden City Moat
Moat of The Forbidden City
military trench
type of earthwork constructed in a military context