...Sir Barnes Wallis, who came up with the idea to ensure that the barrel-shaped weapon would skip along the water's surface and then roll itself down the wall of the dam before exploding at the right depth. Conventional bombs were unable to reliably stay in contact with the wall before exploding.
Wallis devised the bouncing principle by watching children skim stones off the surface of a pond. It was ingenious but miles from being high-tech....
I see that macjules has already pipped me to the post by pointing out that conventional bombing couldn't actually deliver bombs to a precision of inches, and that torpedo nets were the reason for the skipping - and that it was sufficiently high-tech to mean that we don't have the capability to do this today, and would have to re-invent it...
But the real high-tech was displayed in B-W's famous paper "A Note on a Method of Attacking The Axis Powers". In this he points out all the problems associated with bombing from a first principles position - in that you are trying to transfer energy from a chemical reaction to a target through air, which is a poor medium for transmitting energy.
His answer was to transmit energy through the ground, which is a good carrier of pressure waves. You do this by making a large, fast bomb which can bury itself many feet into the ground and then detonate, passing the shockwave into the foundations of the object you are targeting. For viaducts and bunkers it's important NOT to hit the object, which will almost certainly resist a direct strike - the trick is to get underneath and shake the whole object to pieces rather than break one part of it. Or create a huge hole that the object then falls into....
That's a lesson the Americans failed to learn while bombing Iraq, and I don't think we have any 'earthquake' weaponry even today...