A NASA scientist has discovered a defunct Cold War military base hidden deep beneath the Greenland ice sheet. 

Chad Greene, a cryospheric scientist at the Propulsion Laboratory (JPL), was flying a plane over the enormous glacier when the radar unexpectedly detected something buried within the ice.

Previous radar imaging of Camp Century looked like nothing more than a 'blip,' but the new map revealed 3D structures that aligned with the design and structure of the base.

The camp was spotted around 150 miles east of Pituffik Space Base in northern Greenland. 

'We were looking for the bed of the ice and out pops Camp Century,' said fellow JPL cryospheric scientist Alex Gardner, who co-lead the project. 'We didn't know what it was at first.' 

Camp Century, also known as 'the city under the ice,' was a US military base built in 1959. It consists of of 21 tunnels drilled just below the surface of the ice sheet, spanning a total length of 9,800 feet. 

It was used as a front for Project Iceworm, which aimed to install a vast network of nuclear missile launch sites that could target the Soviet Union.

But due to the instability of the ice sheet, the project - and Camp Century - was ultimately abandoned in 1967, gradually becoming buried in snow and ice. 

The facility's infrastructure now lies beneath at least 100 feet below the surface of the ice sheet. 

Previous airborne surveys that flew over Camp Century have detected signs of the base within the ice.

But those flights used conventional ground-penetrating radar, which points straight down and produces a 2D profile of the ice sheet, according to a NASA Earth Observatory statement. 

The latest discovery used radar to map the surface of an ice sheet, its internal layers and the bedrock below, similar to the way that doctors use ultrasound to see inside the human body. 

Greene's flight, which took place in April 2024, used NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) mounted onto the bottom of the aircraft.

This system doesn't just look downward, it also captures a side-view to image solid structures with more dimensionality. 

'In the new data, individual structures in the secret city are visible in a way that they've never been seen before,' Greene said in the statement. 

The scientists used this data to map the structure of this lost base, and they appeared to match historical records of the planned layout. 

When it was built, Camp Century was publicized as a demonstration for affordable icecap military outposts and a base for scientific research.

The US Army only revealed its true purpose after it was abandoned, informing the Danish Government - which administered Greenland - of Project Iceworm's aim.

Camp Century was one of the first facilities to be powered by a portable nuclear reactor, which supplied electricity and heat. 

When the camp was decommissioned, the reactor was removed and its hazardous waste buried. The remaining infrastructure was left to be enveloped in layers of ice and snow.  

Previously, scientists used conventional radar imaging to estimate the depth of Camp Century. 

This work provides crucial information about when melting and thinning of the ice sheet could re-expose the camp and any remaining biological, chemical, and radioactive waste it contains.

The new UAVSAR image, however, was captured completely by accident. 

'Our goal was to calibrate, validate, and understand the capabilities and limitations of UAVSAR for mapping the ice sheet's internal layers and the ice-bed interface,' Greene said. 

'Without detailed knowledge of ice thickness, it is impossible to know how the ice sheets will respond to rapidly warming oceans and atmosphere, greatly limiting our ability to project rates of sea level rise,' Gardner added.