The Netherbow Port acted like the main gateway into the medieval city of Edinburgh. The first Netherbow Port was badly damaged in 1544, and rebuild further down the High Street in 1606. The new structure held a two-storey spired tower, and a clock, over the arched gateway.
The Netherbow Port was demolished in 1764 by order of the city magistrates, regarded as an obstruction to the flow of traffic in a moment which the defensive structure was no longer required.
Historical references: https://canmore.org.uk/site/52153/edinburgh-high-street-netherbow-port