Cunard and the slave trade.

Here it says that The Cunard Building in Liverpool was one of the centers of the slave trade:

'Liverpool's Cunard building was a main centre for the trade. The slaves were shipped from Africa and the Caribbean to Liverpool's docks.'.

http://www.bbc.co.uk/1xtra/tx/galleries/1191/4/

And here it says that The Cunard Building was built during the first world war, between 1914 and 1918:

'The Cunard Building is a building of elegant proportion, sited on the Pier Head at Liverpool. It was constructed by Holland, Hannen & Cubitts between 1914 and 1918 as the headquarters of Cunard Line, and is now the second of Liverpool's "Three Graces".'.

http://en.wikipedia.org/wiki/Cunard_Building

And also, I've heard on the telly and other places, that this year it is bicentennial for the abolition of the black slave trade.

Here they say it was: 'the first significant step towards the end of slave trading in and to the British colonies.'.

http://www.london.gov.uk/slavery/index.jsp

But I was wondering on a couple of things regarding these issues.

- Like, how can they say on the BBC website that the Cunard was a centre for the slave trade, when The Cunard Building wasn't finished being built until 1918, and the abolition of the black slave trade, started in 1807?

- How was it possible for The Cunard Line, to build The Cunard Building, during the first world war, when like it says here, Britain was heavily involved, as a part of the Entente Powers, in defeating the Central Powers in the war?

'The Entente Powers, led by France, Russia, the United Kingdom and its colonies and dominions, and later Italy (from 1915) and the United States (from 1917), defeated the Central Powers, led by the Austro-Hungarian, German, and Ottoman Empires. Russia withdrew from the war after the revolution in 1917.'.

http://en.wikipedia.org/wiki/World_War_I

- Why are they using the term 'the bicentennial for the abolition of the black slave trade', (like I've heard it being refered to on telly).

And not 'the bicentennial for the abolition of slave trade in general', when they are refering to the abolition of the slave trade in the news?