Some of us like replicating well known spacecraft from fiction. Thanks to a tweet from Notch, I found a webpage which puts their scales into perspective - Jeff Russell's STARSHIP DIMENSIONS
While we may not fit a 1:1 scale Death Star or ID4 Mother ship on our worlds, this may help anyone who wishes to scale one down a little/lot.
ps. It also includes Star Trek and Eve ships. A to-scale Babylon 5 would be ... challenging.
pps. Couldn't find a God Phoenix from Science Ninja Team Gatchaman though.
ppps. They do include some ground vehicles and creatures, e.g those in Starship Troopers