The M100 galaxy, which is about 60 percent larger than the Milky Way, next to the M97 galaxy. From "Galaxy Size Comparison Chart" by Rhys Taylor ...

Acoustic research using a scale model 1/12th the size of Stonehenge finds that the completed monument would have magnified speech and improved musical sounds, but only for those inside the stone ...

O scale trains are 1:48 size models. While there are larger model railroad museums, Gribbell says he believes this is the biggest O scale model one.