Landmarks in Sydney, including the Sydney Opera House, were evacuated.

A hostage runs toward a police officer outside Lindt Chocolate Café, where other hostages are being held, in Martin Place in Sydney on Monday.

Hostages run from a cafe under siege at Martin Place in the central business district of Sydney.

A Sea of Flowers Near Scene; Barrister, Cafe Manager Said to Have Acted Heroically Visitors lay flowers at a makeshift memorial near the scene of the siege in central Sydney on Tuesday.