What is it? A TL-4 pulp-adventure setting, centered on explorer-archaeologists, leveraging Traveller5 mechanics.
The year is 1920. The development of modern archaeology in the 1880s has made discovery a sensation. Remittance men, "second sons", and "retired" legionnaires have found a dangerous and potentially lucrative career in finding, exploring, and (quite frankly) looting ruins.
Of course, not all ruins are worthwhile. Fables are notoriously exaggerated or very light on facts. And the more actual wealth a ruin may have, the more likely it is to be dangerous, due to the environment, local indigenous clans, zealously protective secret societies, or intentional traps in the ruins' designs. The list of deceased or missing "archaeologists" grows faster than the rate of discoveries.
Where is it? The action typically takes place in the terrain and overgrown ruins around ancient but clever civilizations. Occasionally, the action switches to an academic setting. The world is Earthlike with Earthlike countries.
Note that ruins and artifacts can be found in quite unexpected places. Sometimes, hiding places are in plain sight.
Wealthy universities are typical patrons. Wealthy individuals are also patrons. Sometimes, fanatical rulers can be patrons (but those tend to be the least stable).
Who's there? Globe-spanning empires hold extensive lands outside their homeland, but the colonies are invariably tenuous and undergoing revolutions, or are engaged in local wars against states or other colonies.
"Late Empire" is the setting. Empires have global reach but no longer have a strong global army or navy. Their effect is therefore typically felt indirectly, as influence.
How advanced is the technology?
Zeppelins, telephones, radio tubes, and biplanes. Biplanes similar to the Goliath exist as an alternative to travel by zeppelin, and have similar performance, but are limited to a maximum of around twelve passengers. Zeppelins can carry more, but require a very large crew.