New York City underground subway station with people waiting for their train. Original public domain image from Wikimedia… https://www.rawpixel.com/image/3290167/free-photo-image-new-york-15th-street-cc0Free Image from public domain licenseGreen up arrow in front of escalators https://www.rawpixel.com/image/6107984/green-arrow-front-escalatorsView licenseConstruction of the New York Subway (1908) by Grant W Pullis https://www.rawpixel.com/image/13755930/construction-the-new-york-subway-1908-grant-pullisFree Image from public domain license