Dimensional Anchor

You create a ward against magical travel that protects up to 40,000 square feet of floor space to a height of 30 feet above the floor. For the duration, creatures can't teleport out of the area or use portals, such as those created by the gate spell, to exit the area. The spell proofs the area against planar travel, and therefore prevents creatures from exiting the area by way of the Astral Plane, Ethereal Plane, Feywild, Shadowfell, or the plane shift spell.

The spell's area can't overlap with the area of another Dimensional Anchor spell. If you cast Dimensional Anchor every day for 30 days in the same location, the spell lasts until it is dispelled, and the material components are consumed on the last casting.

Ending the Spell. During the casting of the spell you can specify a condition that will cause the spell to end. The condition can be as specific or as elaborate as you choose, but the GM must agree that the condition is reasonable and has a likelihood of coming to pass. The conditions can be based on a creature's name, identity, or deity but otherwise must be based on observable actions or qualities and not based on intangibles such as level, class, or hit points.