Perched on a hillside overlooking Shinnecock Bay in Southampton, NY, this residence seamlessly connects to the original waterfront cottage via an underground passage. Its dark exterior creates a striking contrast to the light, airy interiors, where a panoramic operable glass façade blurs the line between indoors and out. A dramatic grade change from front to back allows for a modest street-facing presence while unveiling three levels of expansive waterside views at the rear.