La Casa Pacifica is a private estate, so it is not a normal sightseeing stop, but its history is part of San Clemente's story. Richard Nixon used it as his Western White House, bringing national politics to this otherwise relaxed stretch of coast.
Most travellers will only note it from context rather than visit directly. It belongs on the mental map because it explains why San Clemente's name sometimes appears in American political history as well as surf reports.