The unexplainability of the ancient ruins frustrated every archaeologist who investigated them.

The unexplainableness of the phenomenon left scientists baffled.

She gave me an unexplaining look.

The scientist presented data about the unexplained anomaly at the conference.

The scientist encountered an unexplainable anomaly in the data that challenged every theory she knew.

She smiled unexplainably when she heard the old melody, as if remembering something distant.

The research team released footage they claimed showed an unexplained aerial phenomenon hovering over the coastline.

Pilots reported multiple unexplained aerial phenomena over the coastal city last night, prompting an official investigation.

Researchers are studying sudden unexplained death syndrome to identify underlying genetic causes.