It's only a 15 hour flight via the Med (the long way) from DC, so
I would assume a 747 can do that easily. We used to fly to Saudi,
and only refueled up in Maine so we had enough fuel for alternates
once we got to England. That was in a 707 type, and they needed
about 15k lbs of fuel for weight and balance. Talk about a
squirrely airplane! Get below 15k and that pig was all over the sky...

I used to joke that we might have to have everyone cram forward
to get the nose down (especially Fat-Jake to 300 lb Chief :-)