Pincio Garden sits on a hill overlooking Piazza del Popolo. This piazza was turned into the oval shape that it is today in the 19th century by Giuseppe Valadier which is the same person that designed the Pincio Gardens. The piazza is very large and open with an Egyptian obelisk in the center and fountains at either end of the piazza. It is spacious and welcoming but has been the host to rather brutal events. In the 18th and 19th centuries it was the site of brutal executions and inhumane riderless horse races. The horses would race from the piazza down Via del Corso wrapped in nail-studded ropes after being fed stimulants and having fire crackers set off at their feet. Executions of condemned men took place here as part of the celebration of the Carnival. An execution has not taken place in this piazza since 1826. The piazza is rather beautiful but does not have a pleasant history.
*Added information from DK Eyewitness Guide to Rome