Terrain has a movement cost and units have movement points. Each of the costs now round down in Civilization VI, instead of previous games where the movement would round up, meaning that if a unit has a single movement left and the Terrain costs more than 1, the unit will be unable to move there. Open terrain, like Plains and Grassland, only consume 1 movement point, whereas more difficult terrain, like Woods and Hills, will consume 2 or more movement points.
Zone of control (ZOC)[ | ]
It is best to use caution when moving close to enemy units. Doing so will often force the unit to be in the enemy's zone of control (ZOC), restricting its movement. If a unit has movement leftover when entering an enemy's ZOC, its movement is stopped or it may attack.