A while back I wanted to make a Gallifreyan city, so i did and here are the instructions for making one.
Also this is my first instructable so any helpful feedback would be appreciated.
Step 1: Materials
First collect the parts and tools.
The only specific thing you need is a cheap wine glass for the dome, it is also possible to do with a light bulb although that is harder.
The base should be flat, round and about the same width as the opening of the glass at least fitting snugly inside. Jar lids work well.
The buildings can be made out of anything you like though you should probably stick with metal. Things like springs, screws, broken drill bits and old keys make good buildings so I would suggest them.
You will also need something to that will fit on the stem so you can cap it once you remove the base of the glass.
Hot glue or epoxy.
Needle nose pliers (optional).
Step 2: Building the City
The first thing you need to do is glue the center building into place. The center building should be taller than the rest so make sure it's not to tall to fit into the glass. Next place the other buildings around it, the taller and thicker they are the closer to the center they should be.
For buildings made out of metal you can use a lighter to melt drops of hot glue that the gun lets out when not being used so that you can save some. But if you do that you should be careful not to burn yourself.
Step 3: Preparing and Placing the Dome
Now you need to break the base off of the wine glass. I suggest using a lighter or match to heat where you want to break the stem and then use an ice cube to cool it down, when the part of the stem cracks you can simply pull it of without risking damaging the bulb.
Next glue the glass onto the city base and glue the cap onto the stem.
Now you're done.