New Delhi, Sept. 5 -- The derailment of a streetcar that is a popular tourist attraction in Portugal's capital killed 16 people and injured 21 others, emergency services said. Police said that 11 of those killed were foreigners.

Officials called the accident one of Lisbon's worst tragedies in recent memory.

Here's what to know:

Investigations underway and wreckage removed

Official details about the crash in downtown Lisbon were still scant Friday morning, but details were beginning to emerge about those killed in the accident. The first investigative report examining what caused the popular Lisbon tourist attraction to crash was expected to be released Friday.

Multiple agencies are investigating what Portugal's Prime Minister Luis Mo...