hospital is a health care institution providing patient treatment with specialized medical and nursing staff
When did humans start using hospital?
best-known type of hospital is the general hospital, which typically has an emergency department to treat urgent health problems ranging from fire and accident victims 
How many categories of hospitals are out there?
We have the specialized include trauma centres, rehabilitation hospitals, children's hospitals, seniors' (geriatric) hospitals, and hospitals for dealing with specific medical needs such as psychiatric treatment (see psychiatric hospital) and certain disease  
Which type of hospital takes better care of patients?
The teaching hospital combines assistance to people with teaching to medical students and nurses.
What does it take to work in such hospitals?
You need to attend a medical school is a tertiary educational institution —or part of such an institution— that teaches medicine, and awards a professional degree for physicians and surgeons.
Thanks for enlightening me about hospitals