First of all, you have to have just pure water Pokemon in your party.eg. no water/ground just water.
So when you have that done all you have to do is press a at the wall so you read it and the when your done it should open. It did for me.
NOTE: this is for the chamber that says water only! OK!
It's either a Ho-Oh puzzle or Aerodactyl puzzle, actually. For the Ho-Oh puzzle, bring Ho-Oh. For the Aerodactyl puzzle, use Flash.
by completing the puzzels in the ruins of alph
Yes, in the Ruins of Alph(uncommon)
You can get a level 1 Palkia, Dialga or Giratina in HeartGold or SoulSilver versions if you have an Arceus in your party. Enter the lone building at the Ruins of Alphs and an event will start where you get taken to Sinjoh Ruins. Talk to Cynthia where she will give you a choice between one of the three legendary pokémon from Diamond, Pearl and Platinum versions.
I'm not sure if Crystal is the same (it should be), but in Silver and Gold versions Unown can be found in the Ruins of Alph.
Its right by the chocobo race track.
you go to the ruins after you completed subspace emissonary
After the Sinnoh dex is completed, you can get the National Dex and access it.
You have to find its fossil this is how u get cranidos to sheldon-armor fossil cranidos-skull fossil.... To get fossils you have to teach one of ur Pokemon rosck smash got to the ruins of alphs or anywhere and find rocks u can use rock smash on Hope this helps :)
By completing the 4 sliding stone panels in caves of ruins of alpha you could complete the ruins.by completing you could get 4 item as gifts.
no it will do everything itself
If you cut the weird, crystal-sort of thing in the Ruins near the place where the Shadow Crystal used to be, he'll pop out. You need a Gallade to do it.