I believe it will be Anzio Beach. My search is in the Pacific so I am not able to help you here. However there are many others on this site that will be able to help you.
Do you have his service number? You can go the the NARA website and print out a form to request his records from St Louis. It takes quite a while to receive them and you may be told the records were destroyed in the fire there in the 70's. Some records may have been but there are other areas that hold records as well.
Was he ever in a VA hospital? If so his records would have been sent to the hospital and may still be held by them.
Do you have his discharge papers? His service number and other information would be on them.
Did he belong to the VFW? To join he would have to give information on his application.
Did he have a military funeral? The cemetery will have information.Newspaper obituary as well.
Several of us have tried to email you but there was a glitch in the system and we couldn't respond.
Hope this helps. Good luck and remember.....don't give up.