In the Tel Aviv Hilton.
Bored from reading materials in preparation for a meeting I was channel hopping and caught the first reports on the news. I called my American colleague to watch and just after he turned on his TV, and while we were still talking on the phone, the second plane hit.
About 30 mins later we had to head off to our meeting - at the end we were told by another colleague that both Towers were gone and a further two aircraft had crashed - we just couldn't believe it.
As we thought it inadvisable to go outside, due to the British Embassy being just across the road, we headed up to the Business Lounge to get some food and watch the news coverage. In there were five or six people from Cantor Fitzgerald, a company based in the WTC, who had watched it all unfold on the TV knowing their colleagues were in the building
Later, during a quick call home to the wife, she told me her London office was trying to contact employees in a subsidiary of theirs based in the towers - with little success. She'd been over to visit them a few months earlier and so knew several of the staff working there.
A horrible, horrible and sort of sureal day.