Longer and deeper than the more well known foot tunnel at Grenwich.
The tunnel takes the approximate route of the Woolwich ferry so if one is out of action you can use the other, or you could do a round trip using both.
LRTS: King George V 0.62km
OG: Woolwich Dockyard 0.79km
OG: Woolwich Arsenal 0.89km
Always check details regarding opening hours, accessibility and pricing before travelling.