Mordenkainen's Private Sanctum

With this spell, privacy is ensured in a room of up to 1600 square feet (40 feet x 40 feet, or the equivalent). From the outside, the windows of the room appear to be dark and cloudy, preventing those with normal vision, infravision, or any other type of vision from seeing inside. Those inside the room can see out the windows as they normally would. No sounds of any kind can escape from the room. Scrying attempts, such as ESP, Clairaudience. Clairvoyance, and crystal balls cannot penetrate the room, and a Wizard Eye cannot enter. The caster can leave the room without affecting the spell.

[Complete Wizard's Handbook]

School: Alteration, Abjuration
Level: 5
Rarity: Rare

Range: 0
Components: V, S, M
Duration: 1 hour/level
Casting Time: 2 turns
Area of Effect: One room
Saving Throw: None

Material Components:
a thin sheet of lead, a piece of opaque glass, a wad of cotton or cloth, and a pinch of powdered chrysolite