Although the turnout turned out to be fewer than what the organisers expected, thousands of professing atheists and agnostics from across America gathered at the National Mall in Washington D.C. on Saturday for their second "Reason Rally."

Lyz Liddell, executive director of the Reason Rally Coalition, said the gathering was meant to show that those who do not believe in a god should be considered a potent political force.

"We say to our families, our communities and ultimately our government, which meets just at the other end of this National Mall, that we exist, we are good without a god," Liddell said, as quoted by Religion News Service (RNS).

"We can bring about social change and we are a growing voter constituency," she added.

Wearing T-shirts and carrying signages containing messages which reject religion and support science, the participants—estimated to be between 15,000 and 20,000—cheered as politicians, scientists and secular leaders delivered speeches calling for freedom of religion and the separation of Church and State.

One such politician was Democratic Maryland Sen. Jamie Raskin, who pointed how "progressive religious reformers of all faiths and secular humanists," by working together, have brought about change in American society.

"Pragmatists all, they were not interested in interrogating each other's private faith but in acting on a common public faith that America belongs to all of us and we should judge people not by their religious identities but by the character of their public actions," Raskin, who is seeking Maryland's congressional seat in the upcoming elections, said during the rally.

The senator further encouraged his fellow atheists to continue working together as they supposedly face "titanic forces of unreason and fanaticism blocking our path."

Other politicians who attended the "Reason Rally" include Democratic Representatives Bobby Scott from Virginia and Tulsi Gabbard from Hawaii.

Former computer programmer Laura Duncan, 57, from Michigan said she is just happy to see other atheists like her come out and show their relevance during the event.

"It's just really nice seeing people who think the same way you do after being isolated for 50 years," Duncan told RNS.