When Gustave Eiffel designed the Eiffel Tower, he created a sky-high landmark for the public—and for himself, he included a secret apartment.

According to Atlas Obscura, the tiny apartment was perched 1000 feet in the air, providing Eiffel with a bird’s-eye view of 1890s-era Paris. He furnished the lofty abode with wallpaper, cabinets, furniture, oil paintings, and a grand piano. There was also a small adjacent room with laboratory equipment, which allowed Eiffel to conduct meteorological observations, The Independent writes.

While many elite members of the public clamored to rent the space, Eiffel shunned their exorbitant offers. Instead, he used it to greet illustrious guests like Thomas Edison (who gave him a phonograph machine as a gift), or as a quiet space for solitary reflection.

Author Jill Jonnes provides a great visual image of what an evening was like in Eiffel’s private apartment in her 2010 book Eiffel’s Tower: The Thrilling Story Behind Paris’s Beloved Monument and the Extraordinary World's Fair That Introduced It. She describes one evening that Edison and other luminaries spent in Eiffel’s aerie:

The guests settled in on the dark velvet settees trimmed in fringe. The walls, a warm yellow, were already covered with framed artistic mementos: photographs, drawings, paintings. “Eiffel has a piano there,” said Edison. “Gounoud, the composer of ‘Faust,’ played and sang, and he did it splendidly, too, despite his more than eighty years.” High above Paris, Gounoud’s music wafted forth as the guests smoked cigars, drank brandy, talked, and even sang, a magical late-summer interlude. Working quietly in the background was American artist A.A. Anderson, best known for his oil portraits, but invited by Eiffel to try to capture Edison’s likeness as best he could in a sculpted bust that would commemorate this occasion of genius honoring genius.

The apartment was closed to the public for years, but in May 2015, Condé Nast Traveler announced that it would open to visitors. You can’t stay overnight, but you can peer into the space—which contains its original furnishings, along with life-size mannequins of Eiffel and Edison—and admire the private hideaway of the famous French civil engineer and architect.

Check out some photos below:

[h/t Atlas Obscura]