Gibraltar has 56km on underground tunnels excavated over the last two centuries; Stuart has been unbearably excited about this.   

These tunnels are from World War II; they go up and down and right the way through the rock.

  

These tunnels date from The Great Siege.

 

They lead to a great big cavern, known as St Georges Hall, that contains lots of big old canon that defended the north face of the rock of Gibraltar.

  

Little windows let in fresh air; steel bars stop Minions from falling out.

 

There is light at the end of this tunnel.