What unusual features is the Ansonia Hotel known for?

The Ansonia Hotel, located on the Upper West Side of Manhattan, is renowned for its unique features that reflect its historic and eclectic nature. Among these is the presence of a rooftop farm, which symbolizes a growing trend in urban agriculture and sustainability in cities like New York. Additionally, it was once home to the world's largest swimming pool at the time of its opening in the early 20th century. This combination of innovative uses of space makes the Ansonia Hotel stand out as a remarkable example of adaptive reuse in architecture and urban living.

Other options do not accurately reflect the notable aspects of the Ansonia Hotel. While the idea of a large rooftop pool and bar or an exclusive nightclub may seem appealing in the context of urban amenities, these features are not part of the hotel's historical identity. The mention of a famous art gallery also does not correlate with the recognized offerings of the Ansonia. By focusing on the rooftop farm and the historical significance of the swimming pool, one gains a deeper appreciation of the hotel's character and its role in New York City’s architectural landscape.