Even Castles made of sand, fall into the sea, eventually. Jimi Hendrix
If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them. Henry David Thoreau
Castles in the air - they are so easy to take refuge in. And so easy to build too. Henrik Ibsen
It's gradually that castles are built. Irish Proverb
Building castles in the air. German Proverb
Many who build castles in the air cannot build a hut on earth. German Proverb