New Delhi. On the night of March 7, 2026, more than 80 Israeli planes dropped 230 bombs in Tehran and central Iran. An underground ballistic missile storage and production site was demolished in this bombing. Hundreds of soldiers of the Iranian armed forces operated from here. A day before this, on March 6, 50 Israeli fighter planes dropped about 100 bombs and completely destroyed the intelligence bunker built under Tehran’s Leadership Complex. This is not the first time, Israel had targeted many underground bunkers of Iran in 2025 also. The question is, how do we find out the bunkers hidden underground? How did Israel know that there were bunkers under the fort and ground?

Actually, modern technology of espionage has made it very easy to find things underground. Satellites roaming thousands of kilometers away in space, high-tech sensors and artificial intelligence together can detect even the activities going on under the ground.

Why is it so difficult to hide a bunker?

It is easy to build an underground bunker, but it has now become almost impossible to hide it completely. The reason for this is the basic needs of the bunker. To run any such facility, electricity is required so that the machines and computers can work. People need breathable air, for which ventilation shafts are built. Scientists, soldiers and technicians keep coming and going inside. Communication system is necessary to maintain contact with the outside world.

Apart from this, during its construction, heavy machines are used, land is dug and a large amount of soil is removed. These activities become the biggest weakness of the bunker, because modern espionage technology detects secret hideouts by detecting these signals.

Radar and thermal technology

Today’s spy satellites use very advanced radar technology. The most important technology among these is Synthetic Aperture Radar (SAR). This technology sends microwave waves from the satellite towards the ground. These waves can penetrate a few meters deep into soil and rocks.

When these waves hit an empty space, tunnel or bunker under the ground, their return pattern changes. Scientists analyze this change and estimate the structures built inside the ground. America’s secret spy satellites use this same technology, which makes surveillance possible day and night and in all weather conditions.

Israel used many techniques to detect Iran’s underground bunkers.

Along with this, thermal imaging technology also comes in handy. Any machine, computer or human produces heat. When machines run inside the underground bunker, this heat slowly reaches the upper surface. The satellite’s infrared sensors detect this abnormal temperature present on the ground surface. This difference is especially visible at night, because the surrounding ground becomes cold while the temperature of the soil above the bunker becomes different, meaning hotter.

electronic signals and vibrations

Not only radar or temperature, but electronic signals also give information about secret locations. Intelligence agencies use Signals Intelligence i.e. SIGINT technology, which detects radio waves and other electronic signals.

If there is unusual radio communication from any area, increased use of satellite phones or heavy electricity consumption, then this activity comes to the notice of intelligence agencies. Apart from this, electromagnetic signals emanating from machines also cannot remain hidden.

Vibrations in the ground during construction also provide important clues. When tunnels or bunkers are built inside the mountains, vibration is created in the ground due to blasting, drilling and heavy machines. Global seismic sensor networks record these vibrations and through scientific analysis they understand that this is not a natural earthquake but construction activity.

Role of drones, spy planes and AI

Now the role of high-altitude aircraft and drones has become very important in modern espionage. Spy planes flying at very high altitudes and drones that stay in the air for long periods of time can keep a constant eye on an area. The multi-spectral cameras installed in these take pictures simultaneously in different wavelengths, due to which the activities happening on the ground can be analyzed in more detail.

Apart from this, satellite analysis based on Artificial Intelligence (AI) has become a very powerful method of espionage. AI can detect even very small changes by comparing old and new satellite images. If suddenly a new road is built in an area, the color of the soil changes, trees and plants are removed or vehicle movement increases at night, then the AI ​​system immediately identifies these changes and provides information.

How was the Fordow Nuclear Facility discovered?

A great example of the combined use of all these technologies is the revelation of Iran’s secret nuclear facility Fordow. This facility was being built deep inside the mountain and Iran was confident that no one would be able to find it. But various satellite monitoring systems picked up signs of unusual structure within the mountain. The thermal sensor detected hot air coming out of the ventilation. Communication signals and construction activities further strengthened the suspicion.