You need to get the Silph Scope from Saffron City. You get it in the building of Silph Co. Once you have it, all you need to do is go back to the floor with the Ghost Marowak, and it will appear. (Note: you can't capture Marowak, its a ghost!)
You must defeat them.
you need to find the silph scope this will reveal the ghost to be a marowak you can then defeat it
Get a Slith Scope and climb the towe. Beware: the ghost Pokemon that you visually see transform cannot be caught with a Pokeball
You have to defeat Koga or the Ghost tower, I think.
There is no ghost tower but there is a lost tower where you find ghost Pokemon on route 209.
You need the Silph Scope to see it, then defeat it.
The ghost runs up past the tower and telescope, and down near the tavern (multiplayer room). You can jump and catch it there.
The towering home of Medivh, the last guardian of Tirisfal. He still occupies the tower... as a ghost form, along with his past servants and guests.
To get past the ghost, you need to get the silph scope. Or you could do it the easy way by getting a poke doll to make the ghost flee.
You will need to have the item called the silph scope which reveals the identity of the ghosts that ghost happens to be the deceased mother of a cubone aka Marowak you will have to defeat her in order to reach the top of Pokemon tower.
In Gold, Silver and Crystal, the Ghost Tower has been transformed into Kanto's Radio Tower and you will no longer be able to explore it.
there is no ghost tower but in kanto theres a indoor cemetery in a town .............. I forgot the name