The excursion program specified a stop of a “day or two” at St. Michael (São Miguel), the largest of the Azores, which was somewhat farther east than Fayal (Charles C. Duncan 1867 [bib10640]). But, as Clemens explained in his first letter to the New York Tribune,

The city was founded by the United States in 1850, as the Atlantic terminal of the Panama Railroad, then under construction to meet the demand during the California Gold Rush for a fast route to California.

The city of Panama was founded on August 15, 1519, by Spanish conquistador Pedro Arias Dávila. The city was the starting point for expeditions that conquered the Inca Empire in Peru.

The Metropolitan Hotel in Manhattan, New York City, opened September 1, 1852, and was demolished in 1895. It was built at a time of a "hotel boom" in response to the opening of the New York Crystal Palace exhibition of 1853.

https://en.wikipedia.org/wiki/Metropolitan_Hotel_(New_York_City)

Demolished in September of 1969