This month, US forces have shot down four aerial objects over the skies of North America, leaving more questions than answers about what's going on in the upper atmosphere.
News of the final unidentified aircraft being shot down surfaced on Sunday night, capping off a bizarre weekend.
It came a week after a balloon with antennae traveled across the United States before it was also destroyed by explosions, becoming the third unidentified flying object to be destroyed in three days.
The largest superpower in the world is currently attempting to make sense of it all with its vast intelligence apparatus.
These are the main inquiries they will be considering.
The three unidentified aircraft that have been shot down in recent days are very different from the large balloon in terms of size and shape.
One is a car-shaped object.
This object, which was "the size of a small car," was flying 12,000 feet (40,000 ft) in the air in the direction of the North Pole without using any propulsion or control systems.
Last Friday, February 10, it was shot down over Alaska out of "an abundance of caution," according to officials, because it posed a threat to commercial aircraft.
The second item is cylindrical.
This was first observed over Canada's Yukon territory on Friday night and was described as having a "cylindrical" shape. On Saturday, it was shot down.
The third item is octagonal.
Fighter jets scrambled from Oregon were unable to keep track of it as dusk fell on Saturday after it was first spotted in Canada, just north of the US border.
It was rediscovered the following day in Montana, tracked across Wisconsin, and then shot down over Lake Huron in Michigan.
Although officials haven't publicly addressed its shape, one, speaking under anonymity, claimed that it had an "octagonal structure" and no obvious sensors.
It was first seen on January 28 in Alaska, then in Montana, and finally on February 4 off the east coast. A Chinese spy balloon traveling at a height of about 60,000 feet, according to the US Pentagon.
The balloon's fragments fell across seven miles of water, sinking to a depth of 47 feet.
In order to reach additional equipment, recovery workers are using boats and mini-subs in addition to collecting some debris.
US officials have provided some details about the balloon, which is 200 feet (60 meters) tall and equipped with multiple antennas, solar panels, and surveillance equipment, but they have not specified what kind of information they think it was gathering.
Both major parties have criticized the lack of information.
Congressman Jim Himes of the House Intelligence Committee said, "I have real concerns about why the administration is not being more forthcoming with everything that it knows.
These four items haven't been the only ones to garner attention in recent weeks.
The Colombian air force spotted a balloon that is thought to have traveled through several Latin American nations.
The issue is whether there are really more objects up there or if the reason is better detection techniques.
The North American Aerospace Defense Command's (NORAD) radar was improved to detect smaller objects after the first balloon was discovered.
We're definitely looking harder now, a US official told Reuters.
The rise in sightings began before the current controversy; a US military report from January listed hundreds of fresh instances of flying objects entering American airspace.
Compared to 2021, there were 366 new sightings that were reported. Six of these were categorized as clutter, while the other 26 were drones and 163 were balloons.
Since the US claimed that China was using the balloon as a spy, relations between the two nations have gotten worse.
Antony Blinken, the US secretary of state, even postponed a trip to Beijing.
The US has alerted other nations by connecting the balloon it shot down in the Atlantic to a global surveillance program it claims China is behind.
The UK government declared that it would take "whatever necessary measures" to protect the nation from the threat posed by spy balloons.
Despite denying they were used for spying and claiming they were weather monitoring devices that went awry, China has admitted responsibility for the first balloon and the one that was spotted in Latin America.
Beijing stated that the US government's destruction of the balloon "seriously violated international practice" and that it reserved the right to "use necessary means to deal with similar situations.".
It has now charged the US with ten airspace violations against China.
The US Air Force commander said he was unable to describe the three most recent objects, how they managed to stay in the air, or their origins during a press conference on Sunday evening.
According to a senior US official who spoke to ABC News, these three aircraft are most likely weather instruments rather than surveillance balloons.