Most of Odessa's pre-Soviet era buildings are constructed from limestone. Not surprising really because the city stands on massive limestone deposits created in the time millions of years ago when large chunks of what is now Ukraine were covered by sea.

The 19th century builders of Odessa realizing what lay beneath their feet began tunneling into the cliffs and mining limestone for construction. The result is a network of tunnels running in multiple layers beneath the city and surrounding areas, the total length of which is estimated to be in excess of 2000 km (although we were also told perhaps up to 4000 miles!). The tunnels (now usually referred to as the Odessa Catacombs) were dug out by hand through much of the 19th century by miners working in desperate conditions - pitch black, cold and very damp.

There are thought to be more than a thousand entrances into the tunnels but almost all now have either been blocked off or their whereabouts are just not known, although one was even discovered fairly recently: we spent a very pleasant few hours in the Shustov Cognac distillery and museum not too far from the centre of Odessa. This establishment (which by the way produced the Soviet Union's finest and Winston Churchill's favourite brandy) has been in the same location since the late 19th century. When the current management was carrying out some excavations a few years back in order to create their museum beneath the distillery, they stumbled across a hidden entrance into the tunnels.

At one time or another, the tunnels were used by smugglers, Odessa's most notorious Jewish gang (led by "Misha the Japanese" - he was actually very Jewish but got his nickname because of his somewhat slanty eyes) and then for a short while after the Romanian Nazi occupation in 1941, bands of partisans fighting the occupiers.

Conditions in the tunnels were awful and not just for the miners. Apart from the darkness, the water table gradually rose so that many of the tunnels flooded. Water also constantly drips through from the ground above, so the dank atmosphere is cold and very damp. Many ventilation shafts were dug by the miners, although the Romanian occupiers blocked as many of these as they could find. The WWII partisans were likely the last major users of the tunnels but with the awful conditions, shortage of food and fuel and after a while little support from the population on the outside, the resistance lasted a fairly short time. (Other than for Odessa's Jews, the Romanians tried to make life as normal and comfortable as possible for the citizens of Odessa so support for the partisans diminished).

Today, a short section of the tunnel network is open to the public - guided tours only. One section has been turned into an underground museum and another section has been left more-or-less in its original state is open to visits by the more intrepid, the four of us included!