Size can be hard to gauge from a picture alone. It’s only when standing on the monochrome marble floor of its soaring atrium that you understand the scale of the George Peabody Library, established in 1866. Greco-Roman-revival columns soar to the skies, detailed in gold leaf. Throw back your head to admire five tiers of cast-iron balconies glinting in the light; peer even higher to spy the pièce de résistance – the atrium’s 18m-high skylight that runs the length of the interior, bathing it in a buttery glow. The size is overwhelming, befitting the largesse of one of America’s earliest philanthropists, George Peabody, who ploughed his banking wealth into the arts. The library’s collection of some 300,000 volumes contains 18th- and 19th-century treasures such as first editions of works by Poe, Hawthorne and Melville, yet remains free to explore, as its founder wished.