Main Story line quest, for the Blades.
http://elderscrolls.wikia.com/wiki/Alduin%27s_Wall_%28Quest%...(sorry the link doesn't paste 100% correctly for some reason)
*** Spoiler - click to reveal ***Part of Act II, following "A Blade in the Dark", "Diplomatic Immunity", and "A Cornered Rat", this is the quest culminating in the introduction of Sky Haven Temple for the Blades quest line in the main story arc.
*** Spoiler - click to reveal ***For the puzzles, from Harrawr 's 360 version:
"Puzzle 1 - A pillar moving puzzle, there will be 3 pillars next to each other, simply rotate the pillars until they display the symbol that is already on the pillar to the far right, the dragonborn symbol. MEMORIZE THIS SYMBOL.
Puzzle 2 - This is a room full of tiles, the only way to avoid setting off the trap, is to step on the tiles that have the dragonborn symbol from puzzle 1 displayed on them."