Han Solo came across the square.
Onrai Square existed on the planet known as Seoul 5.
At its heart was a solitary statue of the Mother Goddess Onrai, overshadowed by the massive structures surrounding the plaza.
Concealed beneath the statue was the access point to Seoul 5's control chamber, housing the three power crystals that sustained the planet. During Han Solo's visit to the planet in 4 ABY, he stumbled upon this control room; however, his actions led to the release of the crystals' stored energy. The resulting cataclysmic event obliterated the statue, the square, and a significant portion of the planet itself.