A CITY BUILT BY IMMIGRANTS—AND BEER

FAR BELOW DOWNTOWN Cincinnati, you'll find large stone-and brick-walled caverns with dirt-strewn floors. Their great arched passageways loom over piles of century-old rubble, vast vats that once overflowed with beer, and recently added stairways to assist tourists passing through.

- ELIZABETH NOLAN BROWN

As with so much in Cincinnati, we can chalk up these places to beer-loving German immigrants. The caverns were built for storing lager back before refrigeration was widespread. Unlike ales, lagers must be aged and stored at temperatures below 40 degrees. For the city's burgeoning German population to make the sorts of lagers they had known back home, they had to dig deep.

“The cities that made a lot of beer between 1850 and 1880, they all had lagering cellars,” says Michael Morgan, author of Over-the-Rhine: When Beer Was King. In many places, these subterranean caverns would later be filled in. But not so here.

Curious Cincinnatians and tourists can now traverse recently rediscovered lagering cellars on tours organized by the Brewing Heritage Trail or American Legacy Tours. For a less rustic experience, they can visit Ghost Baby, a cocktail bar and music venue located in a renovated lagering cellar four stories underground.

A trip to—or below—Cincinnati’s historic brewery district will take you to Over-the-Rhine, just outside Cincinnati's city center. When German immigrants started flocking to the city in the 1800s, many settled just north of the Miami-Erie Canal cutting through central Cincinnati. Locals began referring to the canal, derisively, as “the Rhine,” and the German-heavy neighborhood just north of it as “over the Rhine.” The nickname stuck.

Today this is often relayed as merely a charming little anecdote. But it hints at deep tensions between the city’s earliest settlers and the huge wave of immigrants to come.

CINCINNATI'S POPULATION BALLOONED throughout the 19th century, from 2,540 residents in 1810 to 115,435 in 1850, when it ranked as the sixth-largest American city. By 1900, it had 325,902 residents, according to the U.S. Census Bureau.