Short answers, pulled from the story.
Fort York was originally constructed starting on the 20th of July 1793 when one hundred soldiers from the Queen's Rangers landed near Garrison Creek in Toronto. Lieutenant Governor John Graves Simcoe selected this location to serve as a new British garrison with thirty cabins made from green wood for winter quarters.
American forces attacked the town of York in April 1813 and British commanding officer Roger Hale Sheaffe ordered a silent withdrawal while rigging the fort's gunpowder magazine to explode. The resulting blast launched significant debris into the air onto American forces and resulted in over two hundred fifty casualties including Brigadier General Zebulon Pike.
By 1836 the rebuilt fort included eighteen buildings capable of holding a garrison of six hundred fifty soldiers. An additional three hundred fifty soldiers could be garrisoned in adjacent military facilities after work came to an immediate halt at the end of the war in 1815.
Fort York was designated as a National Historic Site of Canada on the 25th of May 1923. The municipal government of Toronto undertook a two-year restoration starting in 1932 converting the fort into a historic site and museum before it formally reopened on Victoria Day in 1934.
The stone magazine has walls three feet thick featuring a vaulted bomb-proof door. Problems in the magazine's foundations led to the construction of a separate brick magazine while the original contained seventy-four tons of iron shells and three hundred barrels of gunpowder.