The Museum of the City of New York at 1220 Fifth Avenue (at 103rd Street) is an absolute gem that gets overlooked by most tourists. Sunday mornings from 10am-12pm, it's pay-what-you-wish for New York residents with ID - and for visitors, the $18 regular admission is still a bargain compared to $30 at the Met.

The museum tells the incredible story of how NYC became NYC, with exhibits on everything from immigration waves to subway construction to neighborhood evolution. The Timescapes multimedia show on the third floor gives you 22 minutes of pure New York history magic. I highly recommend spending time with the activist New York exhibit - it really shows how this city has always been about people fighting for change.

Take the 6 train to 103rd Street-Lexington Avenue station, then it's a pleasant 4-minute walk through the upper East Side. The museum sits right across from Central Park's Conservatory Garden, so you can easily combine both. Much more manageable than fighting the crowds at MoMA or the Met, plus the views of Central Park from the upper floors are spectacular.

Insider tip: The museum shop has some of the best NYC-themed books and prints I've found anywhere. Perfect for solo travelers who want to understand the real story of this incredible city.