The Undertaker and his wife Michelle McCool are currently in New York City entering David H Koch Pavilion Hospital for Special Surgery. This hospital is considered the best in the country for orthopedics and second for rhuematology.
As noted, The Undertaker was delaying hip replacement surgery until he retired from in-ring competition. The Sun reports that he is expected to undergo a series of procedures.
Here are several photos of him arriving to the hospital:
