Hamas has always had a reputation for having some of the best underground tunnels of any militia.
In a media tour arranged by the Israel Defence Forces (IDF) into Gaza, one of the most impressive examples the Israeli military has discovered was on full display.
The entrance was just inside Gaza, only a few hundred metres from the Erez border crossing with Israel, where there was a gaping hole in the sand.
IDF troops at the entrance to the tunnel they say was built by Hamas
Inside was a heavily fortified tunnel, and without doubt the largest I have ever seen in Gaza.
There was plenty of room inside the reinforced concrete structure. A steel pipe ran along the top of it, and electricity cables dangled inside.
The IDF said the tunnel ran for more than two miles into central Gaza City.
It’s no secret Hamas has been building its underground infrastructure for years. It uses them to transport fighters, not only belonging to Hamas but also other militant groups like Islamic Jihad, from one end of the strip to the other.
They are also used to move and store weapons, launch attacks against Israel and, in this war, to hold hostages.
With every war with Israel, they are destroyed and rebuilt again. But the extent of the labyrinth beneath Gaza is difficult to fathom, it’s believed it may stretch 150-200 miles.
There were no lights inside. The IDF had placed a metal grid on the floor to cover holes in the ground that dropped by up to 15 metres, down to other parts of the subterranean complex.