Egyptian police have clashed with anti-government demonstrators as thousands took to the streets demanding an end to President Hosni Mubarak's decades-old rule.
In Cairo, police fired tear gas and used water cannons on rock-throwing demonstrators Tuesday. At one point, demonstrators climbed on top of an armored police vehicle. Another protest erupted in Alexandria, where demonstrators shouted anti-Mubarak slogans.
The protests, reported by foreign media to be Egypt's largest in years, began peacefully.
Egyptians have been calling for political and economic reforms in protests inspired by demonstrations in Tunisia that led to the ouster of that country's president this month. The rallies are taking place in spite of government warnings that demonstrators could be arrested.
The rallies were promoted online by groups that say they speak for young Egyptians frustrated with the kind of poverty and oppression that triggered Tunisia's unrest.
Tunisia may be too unique to represent the first domino in a wave to end autocratic rule in the Arab world, but a whole lot of Arabs (with varying motives, to be sure) want it to be true.
UPDATE: How the day came about.