void HighBridge::destroy()
{ 
  CityPtr city = Scenario::instance().getCity();
  for( HighBridgeSubTiles::iterator it=_d->subtiles.begin(); it != _d->subtiles.end(); it++ )
  {
    (*it)->_parent = 0;
    city->clearLand( (*it)->_pos );

    std::string picName = TerrainTileHelper::convId2PicName( (*it)->_imgId );
    city->getTilemap().at( (*it)->_pos ).setPicture( &Picture::load( picName ) );
    city->getTilemap().at( (*it)->_pos ).getTerrain().decode( (*it)->_info );
  }
}