The ruins are on Seven Island. You need to go to a cave with a boulder puzzle. You need to put the boulders in the right places so that the ruins can be accessed. When you have the boulders positioned, you will "hear" rumbling on the game and the ruins will be accessible, where you can catch Unowns.
If you are talking about the Dotted Hole on Six Island, then the way to get in is using HM Cut on the door. The Sapphire is inside that cave!
Go to four island and go in icefall cave find HM7 use it to go up the waterfall go to the ladder beat the rocket talk to lorelei leave and go to six island and go to the ruins the scientist should be gone use Cut on the door to open it.
near the ruins of alphaLedyba can be found in pattern bush in green path in six island.
use cut
Go up to the Dotted Hole door on Six Island and have a Pokemon use Cut the door will open without fail but save after entering
In order to open the warehouse door on Five Island, you will have to collect two passwords in order to open the door. The first one is obtainable from two rocket grunt on Mt. Ember (located near One Island), and a scientist at the bottom of dot hole (located on Six Island).
The six island in some ruins.
Go to four island and go in icefall cave find HM7 use it to go up the waterfall go to the ladder beat the rocket talk to lorelei leave and go to six island and go to the ruins the scientist should be gone use Cut on the door to open it.
find the translation key on top of the ruins the answer is open.
i think the ruins have unown in them; when you move the boulders on six or seven island into the holes. it will say there was an earthquake, and then you can go back and find unown.
it is for the ruins you go there and you will find a passage the paper has the password on it *it spells OPEN*
near the ruins of alphaLedyba can be found in pattern bush in green path in six island.
On top of the ancent ruins has the translation key.Next, go inside the ruins and go to the wierd head thing and push the word OPEN.
You find the symbols on the roof of the ancient ruins. and just press them in order to make OPEN.
use cut
u spell "open" with ancient symbols.. the translation paper is on the very top of the ruins
The missing page is on top of the ruins, and shows the translation you need to OPEN the door in the ruins. (Push the rock over to reach the vines, climb and jump to the roof.)
Use the translation in the ruins to press the four teeth that spell "open", then press the nose to open the door. (see related question)