This “concept airship” by Dassault keeps showing up on the interwebs, so I did some quick math to calculate the weight of the water in that swimming pool.
Based on the size of the human figures (assuming the people are 6 feet tall), and assuming the pool is 6 feet deep, a very rough estimate of the water in that pool would be 30,240 cubic feet, or 226,210 gallons, or 1,886,591 pounds.
Just to lift the water in the pool alone would require 31.4 million cubic feet of helium at 60 lb lift per 1000 cu. ft.
That’s 4-1/2 Hindenburgs.
Of course, the airship would need to lift more than just the pool: Engines, anyone? Fuel? How about that hard carapace of a shell?
Which is good, because placing two million pounds of water above the lifting gas would cause this thing to capsize and dump all those people onto the pretty mountains.
And at that altitude, high above those mountains peaks, the helium would expand so much the airship would have to be vastly larger than in that illustration.
And the water in the pool would likely freeze into a block of ice without some rather effective — and heavy! — heating system.
But when some people think about airships, they forget about physics.