Charles Saatchi's new gallery has joined Tate Modern on London's South Bank - with both venues battling for the attention of art-lovers and tourists in the capital.
Tate Modern opened in 2000
Saatchi's collection has received a "warm welcome" from the Tate, which opened in 2000 and lies just a mile down the River Thames.
But what separates the two venues? BBC News Online looked at what each gallery has to offer.
When the Queen toured the newly-opened Tate Modern, she was taken on a "safe route" around the building which avoided some of the gallery's more challenging exhibits.
But it would be hard to imagine what would constitute a safe route around the Saatchi gallery's collection of sensations.
Turning your back on Marcus Harvey's Myra - a giant portrait of the child killer composed of children's handprints - and you are confronted with a series of disembodied body parts hanging from a tree - aka the Chapman brothers' Great Deeds Against the Dead.
While Damien Hirst's shark in a tank is thought-provoking, what would a royal visitor make of his One Thousand Years? It is a sealed unit containing a maggot infested cow's head, which breeds flies that in turn are killed in an ultra-violet trap.
The two galleries are just a mile apart
The first adult visitors on Thursday mused on its allusion to the futility of human existence, but their children greeted this with a succession of "eughs" or unsurpassable laughter.
Art critics might say this collection is a bit passé, but it's a great opportunity for to see some of the notorious works that launched so many careers.
Of course, Tate Modern has its fair share of art that is shocking and contemporary, but it has a much broader remit and a wider selection of works - as befits a much larger, public institution.
Nice view from the Tate - with bank holiday weather
But compared to the Saatchi, the Tate's modern art - like the Habitat-friendly paintings of Mark Rothko, or Monet's once-revolutionary waterlillies - seems positively old fashioned.
Both galleries have prime positions on the south side of the Thames with the Tate Modern based at the old Bankside Power Station, right opposite St Paul's Cathedral.
The Saatchi Gallery is at County Hall, a twenty-minute walk away, alongside the London Eye and opposite the Houses of Parliament.
Tate Modern boasts one of the most awe-inspiring entrances to any gallery in the world. Walking down a ramp you are suddenly confronted with Turbine Hall, a massive enclosure which once housed the power station's heart.
Viewing galleries on the upper floors give you the chance to get another stunning perspective on the huge crane that runs the length of the building, looking down on the exhibitions.
Damien Hirst's Love Lost at the Saatchi Gallery
Its views over the Millennium Bridge to St Paul's are as inspiring as any of the Tate's exhibits.
County Hall is also a massive complex. But only a small amount of it is taken up by the Saatchi Gallery, which shares the buildings with two hotels, an aquarium, an arcade centre and numerous cafés and restaurants.
You also get a rather irreverent feeling, wandering past the controversial artworks in the Edwardian, oak-panelled corridors that once resounded to the chatter of London's worthy municipal men and women.
But it is good to see so much space given to individual works - none of which are fenced off to the visitor.
Many of the major exhibits have their own room. Some are their own room - not least Richard Wilson's 20:50, an entire chamber filled shoulder high with engine oil.
Tate Modern is free, though it charges for some exhibitions. Saatchi costs £8.50 for adults. Not a difficult one to call if you are touring the South Bank with the children.
Tate Modern is the perfect end - or beginning to a walk along the Thames path.
But there's little doubt the Saatchi will be popular, fuelled by the personal mystique of the one-time advertising guru himself and the publicity surrounding the controversial pieces he collects.
360° GALLERY TOUR
Take a look inside the Saatchi Gallery.
Despite their obvious common ground, these two galleries clearly have very different remits.
The vast Tate Modern will continue to be one of the best British institutions, an approachable showcase for a huge range of material.
It is much more than just a gallery - it's a destination, in the same way as the Science Museum, or V&A.
The Saatchi, by nature of its size, and of its strictly contemporary nature, will offer much more tightly-focused exhibitions.
It may not be to everyone's taste, but to see many of the infamous works is thrilling and challenging.
The kids may not enjoy it, but you could always promise them a trip to see a real, live shark in the London Aquarium next door..