An apparent easement is an easement that is self perpetuating and independent of human intervention.  Flow of a stream is an example.  An apparent easement is also an easement which can be enjoyed without an act by any person entitled to do so.

In order to charge the purchaser of a servient estate with notice of an unrecorded easement, the easement must be apparent as well as necessary and continuous, or the marks of the servitude must be open and visible.  It is a well settled general rule that a purchaser of a servient estate is charged with notice of an easement which is apparent[i].

Therefore, one who purchases property is generally held to take it subject to apparent easements of light, air, and view[ii].

[i] Benson v. Fekete, 424 S.W.2d 729 (Mo. 1968)

[ii] Darnell v. Columbus Show Case Co., 129 Ga. 62 (Ga. 1907)