Pokémon Diamond and Pearl/The Lost Tower

There is really only one reason you need to go here, and that is for HM Strength. As for anything else, there are a few other items here, but the trainers are farily weak, so grab what you need, battling the trainers along the way. On the fourth floor you will see two old ladies. One will give you HM05: Strength. The other lady will give you a Cleanse Tag. This item, when held by your lead Pokémon, reduces wild Pokémon encounters by 50%. You're done here for now, so go ahead and head on out!

Points of Interest
This is the only real reason you're here. The lady on the top floor will give it to you.
 * HM 04: Strength

Pokémon

 * Ghastly

Items

 * HM04:Strength
 * Revive
 * Cleanse Tag
 * Oval Stone