if (!(flags & DC_QUERY_COST) && bridge_type == GetBridgeType(tile_start)) {

			return_cmd_error(STR_1007_ALREADY_BUILT);

		}

		/* Do not allow replacing another player's bridges. */

		if (!IsTileOwner(tile_start, _current_player) && !IsTileOwner(tile_start, OWNER_TOWN)) {

			return_cmd_error(STR_1024_AREA_IS_OWNED_BY_ANOTHER);

		}

		cost = (bridge_len + 1) * _price.clear_bridge; // The cost of clearing the current bridge.

		replace_bridge = true;

		replaced_bridge_type = GetBridgeType(tile_start);

	} else {

		/* Build a new bridge. */

		/* Try and clear the start landscape */

		ret = DoCommand(tile_start, 0, 0, flags, CMD_LANDSCAPE_CLEAR);

		if (CmdFailed(ret)) return ret;

		cost = ret;

		terraformcost = CheckBridgeSlopeNorth(direction, tileh_start);

		if (CmdFailed(terraformcost) || (terraformcost != 0 && !allow_on_slopes))

			return_cmd_error(STR_1000_LAND_SLOPED_IN_WRONG_DIRECTION);

		cost += terraformcost;