then...

connecting some buildings together and multi-level cities can be created

escape tower...

building with a escape tower,an extra safety feature. it would be an easy sell to buyers.

collider...

the collider can be used for nuclear fusion with some modifications. high energy ions shooting into a dense cloud of ions will be very easy to make some fusions to happen.

micro explosion...

an engine using micro explosion can be very potent. stars are not too far with this engine.