Yup, almost 70 years old. Though it was the biggest gun ever built:
"Weight 1,350 tonnes
Length 47.3 m
Barrel length 32.48 m (L/40.6)
Width 7.1 m
Height 11.6 m
Crew 250 to assemble the gun in 3 days (54 hours), 2,500 to lay track and dig embankments. 2 Flak battalions to protect the gun from air attack.
Ammunition
High Explosive
* Weight of projectile: 4.8 t (4,800 kg)
* Muzzle velocity: 820 m/s
* Maximum range: 48 km
* Explosive mass: 700 kg
* Crater size: 30 ft (10 m) wide 30 ft (10 m) deep.
AP Shell
The main body was made of chrome-nickel steel, fitted with an aluminium alloy ballistic nose cone.
* Length of shell: 3.6 m
* Weight of projectile: 7.1 t (7,100 kg)
* Muzzle velocity: 720 m/s
* Maximum range: 38 km
* Explosive mass: 250 kg
* Penetration: In testing it was demonstrated to penetrate 7 metres of concrete at maximum elevation (beyond that available during combat) with a special charge ."
The Germans blew it up in 1945 so that it shouldn't fall in the hands of the Allies. It was this gun that Saddam wanted to buy a much bigger copy of to shoot over half the Earth.