I took my mother for a surprise trip to NYC. She got married to my father there in '68. The surprise was manufactured by way of telling her we were going to Australia (we live in New Zealand, so a trip to Australia is not a huge deal, it's the type of thing you could do for the weekend) and therefore she packed a bag and brought her passport. We got to the airport and said "Surprise! We're going to New York!" and she cried her eyes out with delight.
When we arrived, on our first morning, I said "Okay, what do you want to do?"
She said "When I was last here, in 1968, the Twin Towers weren't complete, so, I'd like to go to the top of them."
"Your wish is my command!" I said and off we went to the WTC.
That was the afternoon of September 10th, 2001. Suffice it to say, there was a particular poignancy when we looked out the window at around 8am the next morning.