It started with a mystery: How did molten salt breach its metal container? Understanding the behavior of molten salt, a proposed coolant for next-generation nuclear reactors and fusion power, is a question of critical safety for advanced energy production. The multi-institutional research team, co-led by Penn State, initially imaged a cross-section of the sealed container, finding no clear pathway for the salt appearing on the outside. The researchers then used electron tomography, a 3D imaging technique, to reveal the tiniest of connected passages linking two sides of the solid container. That finding only led to more questions for the team investigating the strange phenomenon.