How crisis was sparked and what lies ahead now
1. Why are so many Egyptians protesting again?
It is one year since the Muslim Brotherhood's Mohammed Morsi was elected president. The opposition are using the opportunity to stage huge rallies to call on him to step down. The protests on Sunday were even bigger than those that toppled ex-President Hosni Mubarak at the start of the "Arab Spring".
2. Wasn't he democratically elected? Isn't that a good thing, even if you don't like Islamists?
That is what the Muslim Brotherhood says. It claims that opposition groups who are entitled to protest have been hijacked by supporters of the Mubarak regime who are trying to mount a coup and force out Egypt's first democratically elected leader.
The opposition say that Mr Morsi has lost credibility and that the country is in danger of economic, social and political collapse.
3. The country's most senior cleric warned of a risk of civil war.
Is that likely?
The good news from Sunday was that the protests in Cairo were overwhelmingly peaceful. That was remarkable especially considering the numbers: perhaps more than two million people were on the streets at nightfall.
4. Can't both sides get round the table and thrash out a compromise?
That is what the Brotherhood is calling for. But the opposition says that the Brotherhood will use its hold on the presidency to force through changes that impinge on personal freedoms.
The main opposition parties and Tamarod, the "Rebellion" campaign which organised the protests and says it has 22 million signatures calling for Mr Morsi to quit, say there can be no negotiations.
5. Can Egypt survive? All we see on television is chaos and protests.
Both sides seem prepared to risk the situation getting worse in order to stand on their principles. © Daily Telegraph, London)