Great Exhibition Hyde Park 1851

What were the opening and closing dates of the Great Exhibition at Hyde Park?
1st May 1851 - 15th October 1851.

Is the Albert Memorial the official memorial to the Great Exhibition?
No it isn't. The official memorial is actually a statue behind the Royal Albert Hall.

Why could the Great Exhibition building not remain where it was. It would surely have been a great tourist attraction? 
Parliament told the designer Joseph Paxton that the building could only remain in Hyde Park for a maximum of six months. This he reluctantly agreed to.

Crystal Palace Park 1854-1936

What is the correct location that the Crystal Palace was moved to. Books variously say Sydenham, Penge, Anerley, Dulwich and even Forest Hill. Which is correct?
This is quite difficult to answer. There are many diffeent opinions. The only certainty is the the building was located on an area known as Sydenham Ridge.

What were the grounds used for before the Crystal Palace was built?
Some areas were farmland and the rest were part of the Great North Wood (hence the name Norwood). There were two large mansions there already - Rockhills at the north edge corner of the park adjacent to Old Cople Lane and Penge Place near the Concert Platform.

What caused the 1936 fire that destroyed the Crystal Palace?
No-one really know the answer but there are many, many theories such as accident, arson, insurance fraud, disgruntled staff, government destruction, etc.
 Crystal Palace - Accident or Arson ? - The Crystal Palace Foundation