 The concept of a professional lifeguard is unknown on Ibiza and Formentera alike; some beach bars do keep first-aid supplies.
There are no lifeguards at Ibiza or Formentera.
mnli hypothesis: There are no lifeguards at Ibiza or Formentera. premise:  The concept of a professional lifeguard is unknown on Ibiza and Formentera alike; some beach bars do keep first-aid supplies.