Art Exhibits in London during our layover

Katharine Kunst offers this advice about some art exhibits in London that folks might want to try to see during our layover.

Two really interesting art exhibits going on while you all are laying over.
At the Tate Modern an exhibit called Global Cities. It takes 10 cities (Cairo, Istanbul, Johannesburg, London, Los Angeles, Mexico City, Mumbai, Sao Paulo, Shanghai, and Tokyo) and looks at this in the present moment and then how they will be into the future using five thematic lenses: size, speed, foprm, density and diversity. I found the exhibit just fascinating. Full full full of information. And asking many interesting questions, not all of which did the exhibit answer. There are other more conventional exhibits there as well. A Rothko room which is a quiet place amidst all the school kids and groups. Helio Oiticica's The Body of Colour which you have to pay to enter.
At the Hayward Gallery is an exhibit by Antony Gormley called Blind Light. One of the most exuberantly creative guys I've seen lately.Concrete and hanging guys and a room filled with fog. Don't miss the piece called Event Horizon which to me was absolutely stunning.
Both of these exhibit are on the south side of the Thames.
From Heathrow, there are two ways to get into London. The Heathrow Express is 31 pounds round trip which is expensive--but it only takes 15 minutes from Heathrow to Paddington Station. You can also take the tube which costs a lot less but takes longer.
If you go the the Hayward Gallery first, you'd get yourself on the Circle line and get off at Embankment, walk across a pedestrian bridge and there you are. From the Hayward it is a simple 15-20 minute walk down to Tate Modern which is a converted power station. (The Cities exhibit is in the old turbine room.)