Building as it will look when completed

Having been round both, I can report that Yorkshire folk will be missing a double treat if they shun these latest attractions. One does worry, though: without wishing to suggest that people are in any way parochial around there, I did fall into the hands of a Rotherham taxi driver who had no idea where the centre of Sheffield was. It was a couple of miles away. About the distance, in fact, that separates London's two Tate galleries. Which is an instructive parallel, since - just as in London - one of these new Yorkshire centres is a purpose-designed art gallery, and the other is a titanic converted industrial building.

There the resemblance ends. The Millennium Galleries are designed by a fast-rising firm of architects, Pringle Richards Sharratt, and, being conceived as spaces off a pedestrian mall, a cultural shopping arcade, are as different from your received impression of a grandly aloof art museum as you could imagine. Meanwhile at Magna - a hands-on science centre made out of the titanic former Templeborough Steel Mill - architects Wilkinson Eyre have exploited the existing industrial heritage of their building much more than Tate Modern ever did in its old power station on London's Bankside.

Chris Wilkinson and Jim Eyre are one of the great success stories of British architecture, emerging from nowhere in the 1990s to stand among the leaders in 2001. An ambitious new exhibition of their work, also opening this weekend, occupies a whole floor at London's Science Museum and has a book tie-in: both are called "Bridging Art and Science". At Magna, given a budget that was tiny by Tate standards, they realised they could make a huge effect simply by dropping four new buildings - representing the elements of earth, air, fire and water - into the Cyclopean spaces of the theatrically-lit steel mill, and slinging walkways between them. It works a treat.