Vision determines what the unit can spot. All units can see terrain, <l:6,104>cities<e>, normal Sea units, and normal Air units. All units except for most Sea units, <l:8,26>Radar Stations<e> and <l:8,27>Sonar Buoys<e> can see normal Land units. Land units, cities, <l:8,23>Listening Posts<e>, <l:8,24>Air Bases<e> and <l:8,25>Strongholds<e> can see normal Land units. Only specialised units can spot enemy <l:6,120>stealth units<e>: Trade, Legal, Spy, Commando, Stealth Air, Subs and Stealth Subs. Some <l:6,118>stealth units<e> (of the Trade and Legal variety) cannot see Sea units.