We live in the backyard of a star. Although generally not classified as such, the Sun is a variable star. The appearance of the Sun changes with time. We now have helioseismology data covering more than two solar cycles that have revealed that solar interior changes too. In this talk, I shall discuss what we have learned about what has changed in the Sun and the mysteries that have been revealed. Those unable to attend the colloquium in person are invited to participate online through Zoom (Meeting ID: 942 0262 2849, passcode 792771) using the link: https://zoom.us/j/94202622849?pwd=dGlPQXBiUytzY1M2UE5oUDRhbzNOZz09 Prof. Basu will be based at the HITS institute for her visit to Heidelberg and will be available for meetings by arrangement with her host, Prof. Friedrich Roepke (roepke@uni-heidelberg.de).