Something I'm working on- originally I intended for this particular species to build cities up in the treetops of massive forests, but that's been done before. So I considered maybe they built their villages on mushroom caps the width of islands on Earth.
Would the fungal growths be too soft to support such villages? Could they even grow large enough to be built on (these particular aliens have a humanoid frame but are somewhat larger than humans, most adults probably stand 7<->10 feet in height. Also individual tribes/villages tend to have a population slightly more than a hundred beings)?