A landowner must take reasonable steps to identify and remedy hazards on their property and warn lawful guests of danger. They could also be responsible for hazards they are not aware of if a reasonable property owner or manager would have noticed the hazard.
This can even extend to criminal acts caused by third parties in some cases. For example, if a property owner is aware of the risk of crime in the area, they can be held liable for failing to implement appropriate security measures to protect guests.