People lead busy lives, so it’s understandable that they don’t think about what they can’t see.

Underground is not very exciting – worms, insects, the occasional rabbit warren and a spaghetti of cables, pipes and sporadic archaeology near towns.

But the sea is different. Thousands of us live within sight of the sea and thousands more come to enjoy our many and varied views across it. But how many have explored what lies beneath its surface?

The Forth can be murky, so fewer divers explore East Lothian than dive Berwickshire where the ‘viz’ (visibility underwater) is generally better. But those that do come speak highly of it; the north face of Bass Rock is rated as the third-best cliff dive in Britain. What makes it so interesting and why are locals and visitors alike uninformed and/or disintrested in what is there?

For there is a great deal. Unlike the coast of Norfolk or Belgium, this is not just a series of flat beaches with sandy shoals offshore. Some idea can be gleaned by anyone who walks any part of our foreshore at low tide. Our beaches are punctuated by rocky promontaries and decorated by offshore islands, carrs and busses, all frozen lava flows from the time when the Bass, Traprain and Berwick Law were volcanoes.

At the lowest of tides (MWLS or Mean Water Low Spring) on charts, acres of brown kelp bob out of the water, hinting at forests continuing well out to sea. Kelp anchors itself to those promontories, carrs and busses, providing habitats underwater as diverse as woods on land.

Closer to shore, green, brown and red seaweeds, bladder wracks, oarweed festoon the rocks, justling with mussels, whelks, limpets and winkles for space. Out of the water, seaweeds look flat and lifeless. But seen underwater they become waving fields of colour where crabs scuttle, shellfish open and light is ever-changing. And then there are the wrecks (but that’s for another column).

Our local fishermen may not ever dive but they know the ‘ground’ intimately, placing their fleets of creels through the kelp because that’s where the lobsters hide. A snorkel and face mask (and, unless you’re tough, a wetsuit) is all you need to see this world and corps-de-ballet sprat shoals or clusters of moon jellyfish floating like living balloons in synchronisation above.

Closer than your local paper shop, you can discover a world you have looked at but – all this time – you have never seen.