Covent Garden is the location of the
Royal Opera House, home of the Royal Opera and the
Royal Ballet, so when it was said that (say)
Maria Callas was singing at Covent Garden in 1958 it doesn't mean that she was dressed in a
gorilla costume, busking, it probably means she was actually
on stage inside the
opera house.
Ticket prices at Covent Garden are frighteningly high, partly because lots of rich, ignorant people are willing to shell out -- correction, have their company shell out -- for the privilege of being seen there. After a recent refurb the pricing structure was changed and it is now even more expensive unless you're rich, in which case your good seats have gone down somewhat.
There are seats along the upper sides called the Slips which used to be extremely cheap because you couldn't see all the stage, so were excellent for ballet. You could in fact easily see two-thirds of the stage at any one time. These have now been substantially bumped up in price too.
The main entrance is in Bow Street, opposite the police station, and you go in via the Floral Hall, which is a visually interesting covered structure.
The theatre was opened on 7 December 1732, the creation of John Rich, the producer who had been successful in 1728 with The Beggar's Opera. The first work performed at Covent Garden was Congreve's play The Way of the World; and the first musical work was a transfer of The Beggar's Opera. Operas premiered there included the Alcina (1735), Atalanta (1736), and Berenice (1737) of Handel; and Weber's 1826 Oberon. Mostly it was a dramatic theatre.
The first house burnt down in 1808. The second one lasted from 1809 until succumbing to fire in 1856, and on 15 May 1858 today's building opened with a performance of Les Huguenots.
The transformation to a full-time opera house happened in 1847, when it was named the Royal Italian Opera, since at that time all opera was sung in Italian. Before this date the principal opera house in London had been the King's Theatre, Haymarket (from 1837 called Her Majesty's Theatre). Covent Garden was styled the Royal Opera from 1892, and it came under Arts Council subsidy in 1946 on reopening after the War.