Portal
Portal is a level six conjuration spell with an instant cast time, a range of five hundred feet and a duration of up to ten minutes. The spell requires concentration to maintain.
While portal is a common word in the vernacular, it was not discovered as a spell until the fourteenth century. It opens two circular gates, five feet in diameter, one near the castor, the other up to five hundred feet away. The gates are always perpendicular to the Earth and can only be created in empty space and must be in visual range of the castor.
The physics of the gates are quite interesting. They are two dimensional and open by fading from a mist, not like an iris as depicted in science fiction. They hover a few inches from the either the Earth or a grounded structure such as a building. One can only enter them from one side and from the obverse they appear as mist and are solid. Should a force of approximately six hundred pounds be placed on the obverse, the spell will fail. Once cast, the castor can rotate the gate horizontally. When the gates close, they fade away. Should an object be in the gate as they close, whichever side has the most mass is where the object will remain.
You would think that a spell such as portal would make security a problem with people having the ability to circumnavigate checkpoints. But, since every wand holds a perfect, unalterable record of every use, the yearly registration along with hefty fines for trespassing, helps to keep people honest.