I can't link to the interactive map, I posted it for the location of the park(s), which weren't in the ghetto. You could find it with a search at http://www.ushmm.org for Warsaw Ghetto Uprising. They footnote 8 as the site of the Grand Synagogue, also outside the ghetto, which the Nazis subsequently destroyed. Someone with more knowledge of the actions will have to fill you in on what might or might not have happened in Saski Park during the Ghetto (1943) uprising. It was the site of a major engagement in the August, 1944 Warsaw Uprising fought by the Polish underground. The two are frequently confused. And many of the positions of the Polish in 44 lay in the ruins of the Warsaw Ghetto from the year before.
As I recall from some article or other, the Nazis made sure to keep the Grand Synagogue just outside the ghetto wall to taunt the Jews - it was very beautiful and I'm sure the pride and joy of the community.
I guess they used it for secular purposes and then destroyed it later in retaliation for the uprising.