diff -Nur -Xdiff_ignore freeciv_cvs/server/cityturn.c freeciv/server/cityturn.c
--- freeciv_cvs/server/cityturn.c	Fri Jan 26 19:09:26 2001
+++ freeciv/server/cityturn.c	Sat Jan 27 13:21:14 2001
@@ -82,7 +82,6 @@
 
 static void disband_city(struct city *pcity);
 
-static void begin_city_turn(struct player *pplayer, struct city *pcity);
 static int update_city_activity(struct player *pplayer, struct city *pcity);
 
 static void worker_loop(struct city *pcity, int *foodneed,
@@ -818,7 +817,7 @@
 void begin_cities_turn(struct player *pplayer)
 {
   city_list_iterate(pplayer->cities, pcity)
-     begin_city_turn(pplayer, pcity);
+     define_orig_production_values(pcity);
   city_list_iterate_end;
 }
 
@@ -1694,8 +1693,9 @@
 
 /**************************************************************************
  Called every turn, at beginning of turn, for every city.
+ And also when caravan helps building wonder.
 **************************************************************************/
-static void begin_city_turn(struct player *pplayer, struct city *pcity)
+void define_orig_production_values(struct city *pcity)
 {
   /* remember what this city is building at start of turn,
      so user can switch production back without penalty */
diff -Nur -Xdiff_ignore freeciv_cvs/server/cityturn.h freeciv/server/cityturn.h
--- freeciv_cvs/server/cityturn.h	Thu Dec 21 14:38:17 2000
+++ freeciv/server/cityturn.h	Sat Jan 27 13:23:30 2001
@@ -38,4 +38,6 @@
 void remove_obsolete_buildings_city(struct city *pcity, int refresh);
 void remove_obsolete_buildings(struct player *plr);
 
+void define_orig_production_values(struct city *pcity);
+
 #endif  /* FC__CITYTURN_H */
diff -Nur -Xdiff_ignore freeciv_cvs/server/unithand.c freeciv/server/unithand.c
--- freeciv_cvs/server/unithand.c	Thu Jan 11 14:42:04 2001
+++ freeciv/server/unithand.c	Sat Jan 27 13:41:59 2001
@@ -1144,10 +1144,16 @@
   /* we're there! */
 
   pcity_dest->shield_stock+=50;
+  
+  	/* It is no longer possible to change production back without penalty */
+  if (pcity_dest->turn_changed_target == game.year)
+    pcity_dest->turn_changed_target = GAME_START_YEAR;
+  define_orig_production_values (pcity_dest);
+  
   if (build_points_left(pcity_dest) < 0) {
     pcity_dest->shield_stock = improvement_value(pcity_dest->currently_building);
   }
-
+  
   conn_list_do_buffer(&pplayer->connections);
   notify_player_ex(pplayer, pcity_dest->x, pcity_dest->y, E_NOEVENT,
 		   _("Game: Your %s helps build the %s in %s (%d remaining)."),