Last week I caught the tail of the heatwave which came through New York City during a visit and that brought back memories of when I was there in August 2001 during a more extreme heatwave. The heat was especially memorable to trigger the recollection as a decade ago my lodging was a hostel w/no air conditioning but luckily my days were spent inside at NYMEX for that week.
A couple years prior I briefly met the owner of my Kansas hometown's hockey team and talked w/him for a minute in the team's locker room about trading because he was a NYMEX local and at the time I was a clerk at the KCBT. In 2001 I'd since moved to Chicago and figured that it'd be cool to be on the NYMEX floor so found his email on the internet and sent a quick note to see if I could come by and hang out. The email was roughly that "I was 21, was NOT looking for a job/to get paid and I'd stay out of the way" but it was enough for him to say sure and the guys I was working with in Chicago also didn't mind me going either.
What a lot of people don't realize was how easy it was to find successful traders to talk to and get small bits of advice from on the trading floor. The local at NYMEX was a really amazing guy and in my experience the successful traders were incredibly helpful to young guys coming up because they knew the difficulty and price of success. On the contrary it was the failed, old men (mostly floor brokerage guys who blew out trying to trade) who were the most discouraging/resentful and had to be avoided.
That week at NYMEX was an amazing experience although there isn't one particular lesson I learned but it was great to observe a successful practitioner by watching and soaking things in. Later that same week I searched around the Bloomberg terminal for contact info on a famous trader/author in NYC to get my book signed and got invited over to his house! It helps to be young and dumb but the overall lesson is that it never hurts to ask.
Museum of American Finance which is located on Wall Street. It's a great place to visit for anyone interested in the markets although I felt it was a bit New York-centric. One benefit of membership to the Museum is a subscription to their magazine Financial History which is fascinating for obscure but straightforward observations of risk management and history.