This is truly incredible. Normally, images and models of the Solar System have either the planets to scale, or their orbits, and occasionally they'll display both to scale but, crucially, not with each other. To do so would mean that either the planets would be too small to see, or the orbits would be too vast to fit in a model. These guys did it anyway. With the Earth as a marble, the Sun became a metre and a half across, and the entire model had a diameter of seven miles.
It truly brings the sheer enormity of the universe into a certain perspective, although it's still an image that's hard to comprehend. Even seven miles is difficult for a human mind to envisage, so taking in the vastness of the Solar System is impossible. In fact, this gigantic orrery only models the planetary orbits; with Neptune at seven miles, at this scale the generally accepted boundary of the Solar System, the edge of the Oort Cloud, would be over 400,000 miles away. A model of the entire system at this scale would actually stretch out past the real Moon.