This NPR Planet Money Indicator podcast episode discusses the 30-year Treasury bond ("long bond"), its history, and its significance as a barometer of investor sentiment towards the U.S. economy. The hosts explain that while the recent sale of 30-year bonds was successful, defying initial concerns, the long-term outlook remains uncertain. The episode traces the bond's history, highlighting its initial use during World War I, its later sporadic issuance, and its eventual resurgence in the 1970s due to increased government borrowing. Experts explain the bond's importance to institutional investors like pension funds and its role as a safe asset and benchmark for other long-term interest rates. The podcast concludes by emphasizing the importance of monitoring the 30-year bond as an indicator of investor confidence in the U.S. government's long-term solvency, particularly given current economic uncertainties and large government deficits.