Catacombs

Catacombs are ancient, human-made underground passageways or final resting place of refuges or subterranean cemeteries composed thereof.  Many are under cities and have served as a refuge for safety during wars or as a meeting place for cults during historic times.

Apse

In architecture, the apse is a semicircular recess covered with a hemispherical vault or semi-dome.

Dervish

A Dervish or Darvesh  is someone treading a Sufi Muslim ascetic path or "Tariqah", known for their extreme poverty and austerity, similar to mendicant friars in Christianity or Hindu/Buddhist/Jain sadhus.

Orchestra

The theatre of ancient Greece, or ancient Greek drama, is a theatrical culture that flourished in ancient Greece between c. 550 and c. 220 BC. The city-state of Athens was its centre, where it was institutionalised as part of a festival called the Dionysia, which honoured the god Dionysus.