A very simple pair of changes to make movement associated with rivers more realistic: 1) Historically, movement on water was always easier than movement on land, and rivers were the main means of internal transportation and trade in tribal and pre-modern national areas. Accordingly, I propose, prior to the industrial age, all unit movement along the sides of rivers be at the speed of the road relevant to the current age. 2) The ability to cross rivers depends on the size of the river, and the location on it of the crossing. Minor rivers (say 4 or fewer tiles in length) would normally be readily crossed by ford or raft, and should be crossable without penalty as if they were flat unfeatured land. Major rivers should be handled according to the position of the crossing as follows: (a) Estuaries (river tiles adjacent to the coast or lake outflow) should be unbridgeable, and impassable by land unit prior to the industrial age, and enterable by naval unit at all times; (b) Lower reaches (non-estuaries nearer the outflow than than the source) should be treated as currently, ie as one-turn limiters unless bridged; (c) Upper reaches (nearer the source than the estuary) should, like minor rivers, be crossable without penalty.