Places for keeping things:
* Aquarium: A place where aquatic animals are kept and displayed.
* Herbarium: A place where dried plant specimens are kept for study.
* Aviary: A place where birds are kept.
* Planetarium: A place where celestial objects are projected onto a dome.
* Sanatorium: (archaic) A place for treatment of the sick, especially those with tuberculosis.
Places for studying or engaging in activities:
* Auditorium: A large hall used for public events.
* Conservatorium: A place for the study and performance of music.
* Crematorium: A place where bodies are cremated.
* Lecturarium: A place for giving lectures.
* Solarium: A room exposed to sunlight, often used for tanning.
Other words with -arium:
* Bibliarium: A place where books are kept or studied.
* Gynaecium: (botany) The female part of a flower.
* Infirmary: A place where sick or injured people are cared for.
* Lunarium: A room or building illuminated by moonlight.
* Sanctuary: A sacred or safe place.
It's worth noting that while these words share the "-arium" suffix, their meanings can differ depending on the context.