Rally in Tahrir Square

Cairo's Tahrir Square, the epicenter of the January 25 uprising that toppled former Egyptian president Hosni Mubarak, witnessed a massive demonstration today under the slogan of — CBS News / Alex Ortiz

CBS News' Alex Ortiz files from Cairo's Tahrir Square, the epicenter of the January 25 uprising that toppled former Egyptian president Hosni Mubarak. A massive demonstration took place Friday, July 29, 2011, under the slogan of "the Friday of Unity and Popular Will."

This demonstration follows weeks of a sit-in put on by 28 liberal and secular political factions. The tents put up by those demonstrators remain in the middle of the square.

Starting late last night, Islamist groups began erecting stages in several areas around the square.

Despite the fact that representatives of the secular and liberal parties and the Islamist and Salafist groups yesterday agreed to put aside their differences and emphasize unity, many of the slogans and signs today had a distinctly religious message.

Demonstrators in Tahrir Square.

A sheikh addresses the crowds from one of the platforms in Tahrir.

Despite the fact that representatives of the secular and liberal parties and the Islamist and Salafist groups yesterday agreed to put aside their differences and emphasize unity, many of the slogans and signs today had a distinctly religious message.

Demonstrators congregate in the heat.

Many demonstrators brought umbrellas with them to shelter themselves from the scorching heat.

Demonstrators in Tahrir Square carry large banners.

Members of the Muslim Brotherhood, al-Gam'aa al-Islamiyyah, and Salafist groups dominated the demonstration in Tahrir. Here, protesters chant, "Islamic, Islamic, not civil or secular."

One organizer on stage sprayed water onto the demonstrators down below to provide some relief from the heat.

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