BALTIMORE (WJZ) — You may have noticed an unusual sight over the Baltimore area in the last few days—a Navy balloon hovering in the sky.

Christie Ileto explains what the blimp is doing.

The Navy is conducting aerial mapping over Baltimore, and it’s caught the eye of many residents far below.

If you’ve looked up lately, you may have spotted a U.S. Navy blimp hiding in the clouds, or hovering over Baltimore’s harbor on clear sunny days.

“I’ve been seeing it all week. Like, every day,” said Ashley Bradley.

Almost 200-feet long, it’s flying over Baltimore.

“Me and my friends were actually talking about it and wondering what it was,” Bradley said.

“I was coming down 95 and I was like, ‘What is with that blimp?'” said Dennis McGill.

The U.S. Navy research laboratory says the blimp is a government research airship conducting aerial mapping, and that the MZ-3A lighter than air blimp began roaming above the D.C. area on Sept. 21 and can remain stationary for more than 12 hours.

The blimp is mapping in the flight restriction zones around Washington, D.C. It includes places like the Department of Agriculture and some of our major airports like BWI.

YouTube video even shows the blimp propelled by two 180 horsepower engines, landing as far west as the Frederick Municipal Airport.

The “Baltimore Blimp” — as it’s being called online — has even sparked Twitter discussions. People want to know what it’s doing in the sky, while others are just “blimp watching.”

“Usually when they have a football game or something you see a blimp. But this one was, like, way high,” McGill said.

But the blimp won’t be up for much longer. The research lab says after Oct. 5, it’s flying away.

When the mission is complete, pilots will fly the blimp north to a base in New Jersey.

Right now, it is stationed at the Naval Air Station in the Patuxent River.