After filling up in the Old Town, I decided to walk over to the Umschlagplatz, where hundreds of thousands of Jews from the Ghetto were loaded onto trains headed for Auschwitz and other camps. It was a bit farther than it looked on the map, and I ended up walking through a residential apartment complex as well as some uninteresting thoroughfares. I reached the unassuming monument, which from the outside looked more like a bus shelter, and was able to look around on my own. Inside, there were inscriptions in multiple languages commemorating the awful events that occurred here. From here, you can continue down Stawki toward the Jewish Cemetery, which looks to be quite large (at least on the map.) Unfortunately, I didn't have the time or energy to go, but will certainly make the effort when/if I return to Warsaw.