Legions trained in the "tunnelling" specialist skill are able to create networks of locations under the ground. Tunnels have been used to launch surprise attacks and to avoid strongly defended locations standing between you and your objective. There are rumours of a multi-level tunnel - blocked only in a few places - going all the way from Parrius to the Moonstone Lake by Thakria.
To begin a tunnel you will need to be deep enough underground to support a solid roof. Tunnelling at a depth of less than TWENTY FEET may create new locations down from the surface but this will be an extended trench - no roof but sky - more strategic than secret. Trenches are detailed in HELP TRENCHES.
Syntax: APPROACH DIGGING.
ALL proactive legion activity involving digging into the ground (tunneling, trench-work, terrain alterations) require the "digging" approach.
Syntax: TUNNEL <compass direction>.
Cardinal compass directions only; the legion will tunnel along roughly the same depth and must be deep enough - dug to at least twenty feet or completely inside a trench. All men deployed will set to work creating then extending a tunnelhead in the direction specified. It will take some time and will initially only be narrow, so will not allow many men to pass. Allow the tunneling to continue and the way will be made wide enough for sufficiently large numbers.
NOTE: it is only possible to make tunnels along routes and in compass directions that follow the available directions/adjacent locations found on the surface, i..e. if you are 100ft underground and you try to TUNNEL NORTH it will be possibly only if the surface location 100ft overhead has a permanent exit north to one of its neighbouring locations. Example: tunneling from deep below the "Path entrance" location can only be done NORTH, EAST, SOUTH, WEST because those are the available exits at "Path entrance" itself.
Syntax: TUNNEL UP.
Tunnelling up is slightly more difficult and involves digging up through the roof or ceiling of a location to connect whatever is above - including the surface - with the underground tunnel, trench, cave or other netherworldly location. Upward tunnelling works similarly to direction tunnelling with the main difference being your legion will need to have a platform bringing it within reach of the top of the locale (type LOCALE to see roof/ceiling height). Barricade raising is the common method: use BARRICADE to a number of feet less than 5 from the roof/ceiling then issue the TUNNEL UP. See HELP DIGGING for info on raising obstacles and increasing point height.
EXTRA: it is possible to collapse tunnels - to force a cave-in - and this is achieved using beieging equipment (such as mortar-bombs) to destroy tunnel locations from a safe distance. See HELP BESIEGING.
Related help on terrain and its altering: HELP TERRAIN, HELP DIGGING, HELP TRENCHES.
