4th Gen Solaceon Ruins

The Solaceon Ruins, like the Ruins of Alph in Johto, are an area in Sinnoh where you can explore and find the Pokemon Unown. In Platinum, the HM Defog was put into the ruins as well. Unlike in generation II, however, there is no puzzle to solve to get more Unown. The Unown are simply just in different rooms.

Near the Solaceon Ruins, however, there's a young child that will give you letter seals if you shown him various Unown.

The Solaceon Ruins, however, are an optional area at best, as it's not really required to go there to progress with the story.

Did you explore the Solaceon Ruins? What did you think of them?

I really enjoyed this whole area of Sinnoh so yeah I explored the whole thing

Oh yeah I remember Solaceon Ruins.

Though to be honest I only went in a couple times (Sort of a SQUIRREL) mentality and explored both times with not much else going on. It had some okay items to pick up so.... Yeah, not something to buy a T-Shirt saying I've been there before sort of place. At least to me anyways.

I remember them, and catching Unowns to get the Poke-Ball seals. And some items like Rynamite said. I was disappointed it wasn't anything more though. Actually, I'm still annoyed that the Unowns are all practically pointless and nothing has been done with them. Like the Ruins of Alph in GSC were creepy and the music was unsettling, and you had to catch all 26 of them to unlock the Unown Pokedex.

Its a shame Game Freak has done nothing much major with them. Like if you catch all of them you open up some new significant area or they're required to get a mythical Pokemon etc.

Also... what happened to the PokeBall Seals... it was a way to customize your "Pokemon" even more.
It was sad that when you transferred your pokemon to Gen 5 and up or traded to HGSS that the seals weren't a feature anymore.

Like many things, it was a feature I didn't fully comprehend in my first few saves. I'm sure I got super into seals in my last Platinum save though. Combine that with a brief attempt to capture the maximum possible 398 Pokémon in my Gen IV games and I actually did "catch 'em all!".

I think I just explored like the first few rooms, caught an Unown, and never went back there. I might do that sometime in the future, I never fully explored Platinum.