diff server/maphand.c server/maphand.c
--- server/maphand.c	Sat Aug 26 17:48:47 2000
+++ server/maphand.c	Tue Sep  5 09:30:09 2000
@@ -626,7 +626,19 @@
 ***************************************************************/
 void map_change_seen(int x, int y, int playerid, int change)
 {
-  map_get_player_tile(x, y, playerid)->seen += change;
+  struct player_tile *ptile;
+
+  ptile = map_get_player_tile(x, y, playerid);
+  if (map_get_known_and_seen(x, y, playerid) &&
+      ptile->seen + change == 0 ) {
+    struct packet_generic_integer rpacket;
+    unit_list_iterate(map_get_tile(x, y)->units, punit) {
+      rpacket.value = punit->id;
+      lsend_packet_generic_integer(&game.players[playerid].connections,
+                                   PACKET_REMOVE_UNIT, &rpacket);
+    } unit_list_iterate_end;
+  }
+  ptile->seen += change;
 }
 
 /***************************************************************
diff server/unitfunc.c server/unitfunc.c
--- server/unitfunc.c	Mon Sep  4 18:25:25 2000
+++ server/unitfunc.c	Tue Sep  5 09:30:09 2000
@@ -2937,6 +2937,7 @@
 {
   struct packet_unit_info info;
   struct packet_enemy_unit einfo;
+  struct packet_generic_integer rpacket;
 
   if (dest==NULL) dest = &game.game_connections;
   
@@ -2952,8 +2953,13 @@
       if ((pplayer && pplayer->player_no == punit->owner) ||
           (!pplayer && pconn->observer))
         send_packet_unit_info(pconn, &info);
-      else
+      else {
         send_packet_enemy_unit(pconn, &einfo);
+        if (!map_get_known_and_seen(info.x, info.y, pplayer->player_no)) {
+          rpacket.value = punit->id;
+          send_packet_generic_integer(pconn, PACKET_REMOVE_UNIT, &rpacket);
+	}
+      }
     }
   }
   conn_list_iterate_end;