Recently (well, a good year or so) renewed and with a marked path leading to it, watchtower offers a wonderful view over town of Celje. It's placed on the edge of the Celje forest hill above city park, right next to the Church of Sv. Miklavž. There are quite a few paths leading to it, they are all well marked. Here's one that I usually take.

Cross the bridge over Savinja that heads to Laško. Turn right at the end of the bridge and after 100 meters you'll see a bar on the left, next to the stairs to Kapucinska church. Turn left there and follow the road uphill. It's a bit steep part, but short. After four or five minutes you'll see the ruins of  a Roman temple on your right. Maybe you can take a few minutes to see that one a bit closer. It's nothing much, few collums and  pieces of wall. 50 meters ahead on the road you'll see a big board on your left, pointing up the wooden stairs. That's the start of your »climb« begins. Stairs soon make space to a forest path. Last time I was there it was a bit ruined because of the works in forest (cutting down sick trees). I'm guessing it's back to normal by now. Anyways, follow the marks »Razgledni stolp« and in about 10 minutes you'll find yourself on the crossroads: right and up it's the path for church of Sv. Miklavž, down and left a path to Kapucinska church / monastery, up straight is our path to the watchtower. Don't worry, there are marks for all three destinations.  Ten more minutes and you find yourself above Celje.

The whole »trip« takes around 20-25 minutes. It's short, a bit steep and well worth the view. On your way down you can descent to Polule, a neighbourhood by the main road to Laško or you go back the same way and take the path to Kapucinska church, or to the park… Choices are really there, all paths are marked, so no worry. If you find yourself in Celje and you have less than an hour and no car to take you to the castle, then this is your view point. I'm sure you'll enjoy it. Suitable for all, little children too.