Note: This information was taken from TSR's original AD&D adventure, the Temple of Elemental Evil.
For the DM: No detect spell other than detect magic works in this room. The latter finds the whole room radiating a dim magical essence, with a more powerful dweomer coming from the crystal sheet (see below).

For the players: The floor here is of white marble, the walls and vaulted ceiling sheathed in pearly alabaster. There is a "right feel" to the place, as a place of safety in a storm of evil. The room is bare and clean. A sheet of cloudy crystal substance seems to be set into the northern portion of the east wall. As you look, it begins to brighten, its radiance actually lighting the room! Two manlike creatures with wings of snowy feathers and radiant faces, robed in purest white, appear amidst golden tinted, cloud-like billows. A pale blue sky can be seen behind them. They first peer out at you, and then one speaks in dulcet tones, "What are fair and just folk such as you doing in this foul place of pain and base wickedness?"

For the DM: At this point, prompt answers from the party through further utterances from the angelic duo. Threaten a bolt for any "servant of Evil" daring to enter this "sanctuary of Good. " After sufficient questioning, the two figures smile benignly upon the viewers. They relate that their attention extends to this place because, when the Temple was overthrown, luz (in His generosity and renowned kindness) placed this haven here, so that opponents of the Temple might find refuge in need and gain help against their foes.

For the players: The brighter of the two radiant figures now speaks again. "Now, good folk, place each and every weapon you possess, all of your holy symbols, magic items, silvered items, and magical herbs before this crystal -- the Window of the Planes of Weal -- and then quickly step out of the west door. Count slowly to 77, and do not return in that time, for we shall send a Ray of Just Might through these items. Any flesh in the place would be blasted to oblivion by the ray, and any mortal eye beholding its glory would be forever blinded. But all your items will be made more effective by a factor of + 1, recharged by seven, or otherwise doubled in efficacy -- though this power lasts but seven hours. Hurry! We must act now, for our time is fast running out. We can help but once per seven days, you know!"

For the DM: If the party hesitates, the crystal slowly darkens into cloudy obscurity after one round. If the party complies with the requests, refer to 208 below. The crystal is a magical one-way mirror, protected by a powerful and permanent force field which makes it impervious to harm by anything less than a godling. Nothing can be seen in or behind it, even passwall and glassee being useless against its mighty dweomer.