On a frigid Thursday morning in one of New Orleans' most famous cemeteries , Robert Florence and I strolled past the tall iron-clad gates, eyeing the weathered aboveground tombs that have become a symbol of the Crescent City's past.

The sky, buried in clouds, cast shadows upon the empty grounds as we toured.

Florence, who has been researching New Orleans' cities of the dead for decades, walked carefully through the rows of graves in St. Louis Cemetery No. 3, musing about their often misunderstood history.

In the city's earliest years, its cemeteries were entirely underground, he explains. That was, of course, before yellow fever cursed the city and the low water level exhumed bodies from the ground during flood season.

Before establishing the first cemetery, early New Orleans residents would bury their relatives in the levee to avoid negative impacts from the low water table.

But in 1788, one of the city's most destructive fires ravished the city, destroying 856 structures out of the over 1,100 buildings in New Orleans.

It was no longer spatially feasible after the fire for residents to bury their loved ones along the riverbank since so much of the city was burned, yellow fever decimated the population and caskets continued to pop out of the ground.

Florence wrote his book "City of the Dead" about the history of St. Louis Cemetery No. 1 that "it [was] easy to conceive ghastly notions of the the French Quarter's first inhabitants seeing friends and family float by their front doors during heavy rains."

The city's clear need for a new burial ground in an area away from the riverbank created one of the region's first aboveground cemeteries. But whether it was the low typography or another influence that made New Orleanians switch to aboveground tombs is still up for debate.

"There is sort of a controversy or argument amongst people interested in history or culture on the reason to have aboveground tombs," Florence said.

"Some people will solely point to the typography and the geography and high water table. Other people say 'No, that's not true, that's a myth, that's sensationalism.'"

The real story of New Orleans' graveyard designs

In 1724, the city finally built St. Peter Street Cemetery, a below ground cemetery located in the French Quarter just outside of the city's early perimeter.

Rediscovered in 2011, the cemetery was in operation until the late 1700s, when flooding made it difficult to access.

As disease ran rampant, coursing its way through the living and dead, residents needed more room to quickly dispose of their relatives.

The Spanish, who had taken control of Louisiana from the French, decided the burial grounds on St. Peter Street were overcrowded, and, in 1789, began to build a new cemetery: St. Louis No. 1. Here, the Spanish implemented the unique burial practice — oven vaults — as a way of mitigating disease and addressing the region's low sea level.

"The Spanish invented the ovens in the cemeteries which are the big walls with the arched openings," Peter Dedek, a Texas State University history professor and author of "The Cemeteries of New Orleans," said. "And it's around the Spanish period that they start to appear."

Since aboveground plots were reusable and could house several bodies, this style of burial became increasingly effective to curb disease. According to Florence, one wall vault could fit several hundred bodies by moving the caskets to a lower receiving vault in the chamber of the foundation.

This was highly effective, especially in 1853, when New Orleans experienced one of the deadliest yellow fever epidemics that killed 8,000 residents.

A year later, St. Louis Cemetery No. 3 was constructed.

The French connection

According to Florence, aboveground burial has roots leading even further back to the Mediterranean. To this day, you can still find traces of aboveground burial sites in the south of France, Spain and Italy.

Once France acquired Louisiana from Spain in 1800 and took control in 1802, the aboveground burials continued, possibly influencing Francophone leadership to follow suit overseas.

As yellow fever was raging through New Orleans in the 1800s, France was also battling the epidemic. There, officials banned cemeteries from being built in residential areas, hoping to slow disease.

In the late eighteenth century, a group of cemeteries were constructed outside Paris' city limits. The Père Lachaise cemetery, built in 1804, bears a striking resemblance to the cemeteries in New Orleans, where aboveground tombs were already being used.

However, according to Dedek, most of the bodies at Père Lachaise are actually buried underground, below the raised tombstones.

It has been nearly two centuries and aboveground tombs are still being used in New Orleans. While the city is no longer scrambling to address the heightened death toll, the vaults have been passed down generations to fulfill family legacies.

"Cemeteries are not for the dead, they're for the living," Florence said.