It is a line in the sand that runs down the middle of a street in one of the Gold Coast’s most affluent beachside suburbs.

Peerless Avenue at Mermaid Beach is what locals have dubbed a “dam wall for development” that is holding back a surging tide of tower projects.

Bookended by the millionaires row Hedges Avenue and the Gold Coast Highway, its northern side marks the southernmost edge of the city’s unlimited building height zone that runs up through Broadbeach, Surfers Paradise and Main Beach.