A hundred years ago on Monday, the once prosperous passenger pigeon became extinct. At the Cincinnati Zoo, Martha, the last surviving member of this iconic species, died at the age of 29.

Her death marked the loss of perhaps one of the most abundant birds on the planet, which at one time numbered in the billions. In the 1800s, swarms of birds could pass overhead for hours, or even days. According to The Associated Press, their numbers reached as high as five billion at one point, with one flock spotted in Ontario in 1866 taking 14 hours to pass.

"As time went on it became clear that those clouds were birds," expert Joel Greenberg told NPR. "And as more time passed, they were plunged into darkness. People who had never seen the phenomenon before fell to their knees in prayer, thinking the end times had come. The down-beating of hundreds of millions of wings created drafts. People were cold."

But, this species was no match for humans, whose rapidly advancing technology and over-hunting drove the birds to extinction in a matter of decades.

"The demise of the passenger pigeon is one of the fastest and most dramatic extinctions ever witnessed, and ultimately caused, by humans," wrote the London Zoo.

The loss of this species is so great, that a team of geneticists are currently working to bring the extinct passenger pigeon back to life using DNA technology - a process known as de-extinction.

"The goal... is to bring the passenger pigeon all the way back using the genome of the band-tailed pigeon and state-of-the-art genomic technology," wrote the group Revive & Restore. "The genomes of the two birds will be compared in close detail, to determine which differences are most crucial. The data and analysis will begin with the process of converting viable band-tailed DNA into viable passenger pigeon DNA."

The passenger pigeon, or wild pigeon, ranged from central Ontario, Quebec, and Nova Scotia south to the uplands of Texas, Louisiana, Alabama, Georgia, and Florida, according to Encyclopedia Smithsonian.