New York is best understood on foot and from above. Start early with the ferry to the Statue of Liberty, walk Lower Manhattan to the One World Trade Center and head up the Empire State Building observatory to see the whole city. At night: Grand Central, the lights of Rockefeller Center and St. Patrick's Cathedral. On another day, the dinosaurs at the American Museum of Natural History, Times Square and Hudson Yards at sunset, before leaving the city across the Brooklyn Bridge.
2 or 3 days cover the essentials if you group each day by area (Downtown, Midtown, Upper West Side) and ride the subway. Build your itinerary with AI: what to see in each time slot, transfers, a day map and an estimated budget in dollars.