Teardown

It's the capability to get your Buildings down one level at the expense of some resources, so you can get that extra field back, each Teardown cost a percent on the building itself, that is 33,33%. So if the building costs 100 ore 100 crystal 100 hydrogen it will cost 33,33% of the total value to tear it down, which is 33 ore 33 crystal 33 hydrogen.