* @param unit The <code>Unit</code> to set the destination for.
     * @param destination The <code>Location</code> to set as destination.
     * @return An <code>Element</code> encapsulating this action.
     */
    public Element setDestination(ServerPlayer serverPlayer, Unit unit,
                                  Location destination) {
        if (unit.getTradeRoute() != null) unit.setTradeRoute(null);
        unit.setDestination(destination);

        // Others can not see a destination change.
        return new ChangeSet().add(See.only(serverPlayer), unit)
            .build(serverPlayer);
    }