I went on a hunt for a few of these when I was in Stockholm recently and it was a bit disappointing. We couldn't find a sign at the globe and lots of places were shut. Venus is now a building site and we couldn't find Jupiter at the airport. We found the Earth and moon, Mars and Mercury (from a distance). It is a good way to explore and you get good value out of a T-bana pass.
Edit: If anyone is interested I can write up the hunt. Got some good photos. It was this or a visit to https://en.wikipedia.org/wiki/Ytterby and I think the solar system was the best choice. They should really promote these attractions more.
Solar Systems in scale are really impressive. We usually see them in books, where all the planets are close. The amount of space is astonishing. I saw one in Brazil in a Astronomy Museum http://www.mast.br/, the Sun is smaller than a golf ball and you have to walk dozens of meters to get to Uranus. The nearest star would be in a city more than a thousand kilometers away. This is what I call a humbling experience.
The system is at scale 1:680 000 000. Earth's model is about 1.9 cm in size and at 225 m distance from the sun's model, while Pluto's model is 7.7 km away from it...
We have one in Australia too - I drive it several times a year.
Distance sun to pluto is 190 km unfortunately - I visited the wiki link ready to hurl abuse
Unfortunately, due to its name, Uranus has been the butt of many jokes.
Sorry -- had to share that. Got it from the wonderful "Great Courses" intro to astronomy series (See? I managed to throw in some good hacker stuff and tell a corny joke at the same time.) Highly recommended.
There's one in Denmark as well, although much smaller (1: 1 billion). One thing that I thought was really cool when I visited was that if you stood by the fake earth an looked at the fake sun it appeared precisely the same size as the real sun. Also very cool to walk for a couple of hours and reaching tiny Pluto.
Not on the same sort of scale at all, but York (UK) has a scale model along one of the Sustrans cycling routes: http://www.york.ac.uk/solar/
SkyRide do free regular guided public rides down the route (or sometimes a subset there of for people who don't feel up to the full length and back) which is a pleasant way to spend an hour or two if you are in the area.
How accurate is it? It seems that a lot of locations were picked because of them being in museums and other significant places. I guess if it was really accurate they would end up in more inconvenient spots.
Earth's distance from the Sun varies by +/-~2% at its current eccentricity, and the eccentricity isn't constant. So at a distance of ~7.5 km (1:20 mil of Earth's average orbit) you've got a ring about 300 m wide around the Sun to find a museum in.
Other planets further away give you larger rings to search in; you could place Jupiter in a ring ~4 km wide ~39 km away, and it would be within the range of its orbit around the Sun.
That said, while the task is easier than you might think (since there isn't One True Position for each planet), I don't know how well they did.
Does anyone have a decent photo of the one (Saturn) in Uppsala? Surprisingly, I can't find any photo on the internet (searching in either English or Swedish), I lived there in 2012 and don't remember seeing a 6.1m circular object in Celsiustorget at all.
It was a temporary thing during the "year of astronomy"; the mat was on the shopping street just outside the old Celsius observatory. For the time being there is no Saturn as far as I know. But its moon Titan should still be hanging at the same spot, a ~40cm semi-translucent sphere to represent the thick atmosphere.
I seem to recall reading about a scale model of the solar system somewhere in the northern hemisphere that 'included' the nearest star in Australia somewhere... Anybody else heard of this?
Edit: If anyone is interested I can write up the hunt. Got some good photos. It was this or a visit to https://en.wikipedia.org/wiki/Ytterby and I think the solar system was the best choice. They should really promote these attractions more.