Some of Team GB’s greatest athletes have been giving us their tips on what to see in London. Here are the results:

Afternoon Tea
Silver medal winning rower, Zac Purchase loves a traditional afternoon tea: “One of my favourite things to do is to have afternoon tea. It’s such a fantastic British tradition. Choose a good hotel or restaurant and dress up. Make an occasion of it, and you won’t need any more food for days!”

The O2 (North Greenwich Arena)
Bronze medal winner in the team Gymnastics, Louis Smith is a big fan of watching gigs at The O2. With big names like Cheryl Cole, Jessie J, Justin Bieber and J Lo all performing at the venue in the coming months, this Olympic venue has got a lot to look forward to.

Oxford Street
When she’s not perfecting her heptathlete events, gold medal winner Jess Ennis is a big fan of shopping on Oxford Street. Home to some of London’s greatest department stores, as well as that gigantic Top Shop, it’s no wonder Oxford Street is a favourite with this London 2012 legend.

St Paul’s Cathedral
Triathlete Helen Jenkins picked out St Paul’s Cathedral as her must-see London attraction. One of London’s most iconic landmarks, St Paul’s should definitely be on any history or architecture fan’s sightseeing bucket list.

The Thames
Silver-medal winning rower Mark Hunter, a qualified Thames Waterman, suggests a trip down the Thames as his unmissable London activity. If you’re not into rowing yourself, why not try one of the riverboat cruises or even a speedboat tour on London’s most famous river? You can even take a kayak down the Thames…

Nelson’s Column
The central Trafalgar Square landmark is a favourite for sailor Ben Ainslie. I wonder what Ben makes of Lord Nelson’s new hat?

Buckingham Palace
Wheelchair racer Shelly Woods picks the Queen’s official residence as her favourite place in London. Perhaps unsurprisingly, as Buckingham Palace will be where she finishes her marathon at the end of The Mall later in the summer.

The top three essential places to visit from a poll of the Team GB athletes are as follows:

• London Eye
• Buckingham Palace
• River Thames

What’s your favourite London landmark? Let us know in the comments below.

Boris Johnson announced the next two commissions for the Fourth Plinth in Trafalgar Square this morning.

Artists Elmgreen & Dragset and Katharina Fritsch are the winners for 2012 and 2013.

Elmgreen & Dragset’s Powerless Structures, Fig 101 is a bronze sculpture of a boy on a rocking horse.

This morning, the artists explained their sculpture is not about victory or defeat. “It’s about play, being part of a game. It’s maybe not about winning or losing. It’s easy for us to stand up here today and say it’s not all about winning, but… We wanted to put something among all the admirals and generals in Trafalgar Square that would perhaps be mocking, perhaps change people’s perspectives.”

The second winner announced this morning is Katharina Fritsch’s Hahn / Cock; a giant, surrealist cockerel in bright blue.

Katharina described her sculpture as a “wake up call” and seemed happy to allow different interpretations of her work from the Mayor and others. (Boris suggested it might have something to do with Tottenham Hotspur, before talking about the idea that this very French symbol will, at least, be looked down on by Nelson from the centre of the square.)

Here’s a rather hastily taken, wobbly video of this morning’s annoucement, where you can see / hear more from the Mayor:

So, what do you think? Are these worthy winners? Were there others in the shortlist (there’s a reminder here) that you would’ve preferred to see on the Fourth Plinth? Let us know in the comments below.

The prize includes two tickets to the National Portrait Gallery’s Thomas Lawrence exhibition, plus a show catalogue and £80 to spend on lunch in the Portrait Restaurant.

At the exhibition, you’ll see more than 50 portraits by the great Regency painter Thomas Lawrence, whose subjects include royalty, international statesmen, society figures and military leaders.

And from the Portrait Restaurant you’ll enjoy amazing views over the London skyline, including Nelson’s Column, the Houses of Parliament, Big Ben and the London Eye.

Enter Day 20: National Portrait Gallery tickets, catalogue and lunch here