Tui Regio is a region on Titan

Titan (moon)

Titan , or Saturn VI, is the largest moon of Saturn, the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found....

 in the southwest corner of Xanadu

Xanadu (Titan)

Xanadu is a highly reflective area on the leading hemisphere of Saturn's moon Titan...

, named after Tui, a Chinese goddess of happiness, joy and water. Tui appears to lack the erosion channels that mark other highland regions on Titan, suggesting it may be geologically young. Patterns resembling lava flows have also been observed, suggesting cryovolcanism.