Two years ago, the Syrian revolution erupted with a full-throated scream of defiance. After years of repression, it shocked even those who were doing the screaming.

"The first protest was so great when we screamed and said 'the people want to overthrow the regime,'" recalled Media Daghestany, an opposition activist and single mother of one from the Syrian city of Homs.

"I screamed, and then went silent to hear, 'Oh, I said that.' And then I screamed again," she said.

For truck driver Abu Mariam, his evolution into an opposition activist occurred after he witnessed Syrian security forces beating demonstrators in Aleppo, the nation's largest city.

"I saw protesters were screaming, "God is great," and they were being stabbed with knives and beaten with electric clubs," Abu Mariam said.

"Automatically, I joined them and started screaming 'God is great.' When I yelled that, I felt like was reborn."

The popular unrest following the first protests in March 2011 has challenged the dynastic dictatorship that has ruled Syria for years.

Today, Syria is being torn apart by a civil war that has killed more than 70,000 people and forced more than one million Syrians to flee the country. The conflict threatens to spill across borders to destabilize neighbors in an already turbulent Middle East.

The opposition says Friday (March 15) marks the second anniversary of the beginning of the uprising.

"Of course, if the revolution was won in the first six months, everything would be easier," Daghestany said, while toying with a necklace decorated with the colors of the Syrian rebel flag.

Daghestany and Abu Marian are two activists who led protests in two different cities at the start of the revolution.

Neither of them expected that the uprising would unleash so much bloodshed and carnage.

Since 2011, their lives have taken unexpected turns, even as Syria itself has undergone violent transformation.

Amateur videos from 2011 show Daghestany dressed in a Che Guevara T-shirt with a bandana wrapped around her face, leading small crowds of women chanting for the overthrow of the Syrian government.

For Daghestany, leftist dissident politics were part of her family's DNA.

"I was against the regime before the revolution. My dad was in prison for eight years and I grew up in a family which hated the regime, the father and the son," said Daghestany, referring to Bashar al-Assad, who inherited the presidency from his father, Hafez, who died in 2000.

Abu Mariam came from a more modest background. He was a truck driver who shipped cargo between Aleppo and neighboring Turkey.

He said he became an opposition leader after security forces threw him in prison.

"They arrested me at a demonstration to honor the martyr Omar al Hawi," Abu Mariam said.

"In the central jail, I met with many Syrian rebels and we started coordinating together. We talked about why my neighborhood, Bustan al Kaser, wasn't participating in the uprising. When I was released I started working with other activists and arranging demonstrations in Bustan al Kaser."