You Have Two Sentences.

After that your player's eyes will glaze over.

Use those two sentences to describe, in bullet point fashion, what is in the area and what exits there are. Lastly capture the vibe, perhaps either by mixing in a well chosen adjective or describing a sensation. 

The goal is to convey as much specificity as possible with the least amount of words, for example "Doberman" instead of "dog."

More details will become evident as players investigate and ask questions of you. Again, when answering focus on limiting yourself to two sentences when possible. This encourages exploration to be a conversation between players and gamemasters.

Bonus sentence! You may follow up these two starting sentences with a third prompting the players such as "What do you do first so-and-so?" or "What would you like to look at first so-and-so?" and feel free to add a "You have ten seconds to decide!" if there is danger.