"spectacular architecture" is correct and usable in written English.
You could use it to describe amazing buildings, monuments, or landmarks. For example, "The Taj Mahal is an impressive example of spectacular architecture."
But in some ways the spectacular architecture undercuts a sense of community.
You note that, in Sagaponack, at least, spectacular architecture ends up detracting from the community.
Can the role of spectacular architecture translate successfully from city to suburb?
A decade of urban development has resulted in some of the most spectacular architecture in Spain.
This new crop of laboratories features spectacular architecture and resort-like amenities.
Lincoln is a peaceful town with two thousand years of history behind it, evident by the city's spectacular architecture.
Spectacular architectures built by the packing of supramolecular soft spheres have also been recently discovered.
The spectacular contemporary architecture, by the New York team of Tod Williams and Billie Tsien, cradles the modest graces of the Merion structure with an air of religious veneration.
This is an impressive area of man-made, natural beauty, combined with some spectacular modern architecture and tranquil botanic gardens in the river's basin.
The journey is rich in history, art, spectacular ecclesiastical architecture and stunning landscapes, which the single-track railway links together like pearls on an iron string.
Between roughly 1600 and 1750 (the dates vary depending where you look) spectacular baroque architecture, sculpture and painting filled Europe's palaces, churches and city squares with giant cherubs, pyramidal ornaments, lashings of gold and opulent baubles.
