Adverse possession is a widely misunderstood method of acquiring property ownership. And it takes a while. The acronym is OCEAN which stands for: Open, Continuous (for 7 years), Exclusive, Adverse and Notorious.
According to the free dictionary online:
"Adverse possession depends upon the intent of the occupant to claim and hold real property in opposition to all the world and the demonstration of this intention by visible and hostile possession of the land so that the owner is or should be aware that adverse claims are being made.
The legal theory underlying the vesting of title by adverse possession is that title to land must be certain. Since the owner has, by his or her own fault and neglect, failed to protect the land against the hostile actions of the adverse possessor, an adverse possessor who has treated the land as his or her own for a significant period of time is recognized as its owner."