A life-altering force of nature can come in many forms—something large enough to inundate a subcontinent, or small enough to grow inside your head.

In the summer of 1869, Agricultural College of Pennsylvania President Thomas Burrowes invited alumni back to campus. Friends from the Class of 1866 enjoyed that reunion so much, they met again the following year to make official their lasting allegiance to one another and to the institution they loved. One hundred and fifty years later, the organization they founded has evolved to be the largest of its kind in the world, connecting alumni, supporting students, and helping lift the university to new heights.