Which historic district in Mississippi was designated a National Historic Landmark for its architecture?

The Natchez Historic District is recognized as a National Historic Landmark primarily due to its rich collection of antebellum architecture, which provides a significant insight into the history and culture of the South. This district showcases a remarkable array of historic buildings, including mansions, temples, and commercial structures that reflect styles such as Federal, Greek Revival, and Gothic Revival.

Natchez's architecture represents not only the wealth generated by the cotton industry in the 19th century but also the aesthetic sensibilities of that period, making it an invaluable resource for understanding architectural trends and historical socioeconomic factors. The preservation of this district allows visitors and researchers to appreciate the craftsmanship and design that characterize this unique region of Mississippi.

In contrast, while the other districts mentioned have their own merits and historical significance, they lack the same level of architectural distinction that has led to Natchez being recognized specifically as a National Historic Landmark for its exemplary examples of historical architecture.