Director’s Diary: Floating City and Honeycomb Rock

This week heritage boat tours and river walks every day, Chamber Music on Wednesday, Secret Adventures in Cinema on Thursday and Midnight Apothecary on Saturday. The calendar for the week is below.
On board Norwegian Cruise Line Epic, nothing but sea in every direction for five days: no ships, no boats, no land. When Jules Verne crossed the Atlantic on SS Great Eastern, he kept a diary and in 1871 published Une Ville Flottante (Floating City), this a factual description of Brunel’s ship interwoven with a romantic story. Verne is right, we float rather than sail or steam, and the effect is vaguely dislocating: in a bubble, in the world but not part of the world. The Great Eastern’s cable and everything that followed has made the world smaller and smaller, but from the deck of a ship – even a large ship – it seems very large place. 
 
Today I am speaking about Atlantic Tunnels: in New York, Gibraltar & London and a new system invented by Brunel that has transformed our cities. New York Subway is mostly close to the surface and what is called Cut & Cover construction: dig a trench, put the railway in the trench, cover it over. The oldest underground railway in the world, the Metropolitan Line in London, was built using this same method. In Gibraltar Royal Engineers dug through Hard Rock to build different and deeper tunnels. Gibraltar is just 2.6 square miles but is honeycombed with 34 miles of tunnels. This is twice the length of its entire road network. The first tunnels served as communication passages between artillery positions and housed guns within embrasures. Over the next two hundred years, more tunnels allowed easier access to remote areas and to stores and reservoirs.
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The 20th century saw by far the greatest extent of tunnelling when the Rock was turned into a huge underground fortress for 16,000 men and supplies, ammunition and equipment: ammunition stores, air raid shelters, underground hospital, storehouse, telephone exchange, power station, water distillation plant, bakery, vehicle maintenance workshop and barracks. The tunnels also housed one of Gibraltar’s most secret places – Stay Behind Cave, built for Operation Tracer, a secret observation post manned by six men within the Rock if it fell into German hands. It was not rediscovered until as recently as 1997. There are nine underground reservoirs,. Tunnelling finally stopped in 1968 when the British Army’s last specialist unit was disbanded. 
Gibraltar’s first tunnels were constructed by hand: slow, backbreaking work. The limestone rock was fragmented by gunpowder blasting, fire setting, quicklime boreholes. hammered wooden wedges and pieces were removed with crowbars and sledgehammers. The tunnels created were 6 ft – 9 ft in diameter with smooth-sided walls. Excavation was slow: 660 ft per year, but the method caused only minimal damage to the surrounding rock and has resulted in very stable tunnels. Later tunnels were constructed at 200 ft per week using explosives and machinery, but produced high-pressure gas which penetrated and weakened the surrounding rock and some of the tunnels are now too unsafe to enter.
 
Brunels Thames Tunnel measures less than half a mile but took 18 years to complete and completely changed the shape of our cities. Blasting through solid rock is hard and backbreaking work, but paradoxically soft earth tunnelling is even harder.
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Sunday 15th April
10.40 heritage boat trip from Embankment tube offered in partnership with London Walks
10.40 riverside walk from Bermondsey tube offered in partnership with London Walks
Monday 16thApril
10.40 riverside walk from Bermondsey tube offered in partnership with London Walks
Tuesday 17thApril
10.40 riverside walk from Bermondsey tube offered in partnership with London Walks 
Wednesday 18thApril
10.40 heritage boat trip from Embankment tube offered in partnership with London Walks
14.00 Training Visit London Fire Brigade
18.15 riverside walk from Bermondsey tube offered in partnership with London Walks
19.30 Eos Trio perform Chamber Music through the ages
 
Thursday 19thApril
10.40 heritage boat trip from Embankment tube offered in partnership with London Walks
11.00 Mudlarking: Foreshore session for volunteers
12.00 Bresmere Primary School
18.00 Secret Adventures in Film with cocktails and warming drinks in Grand Entrance Hall
Friday 20th April
10.40 heritage boat trip from Embankment tube offered in partnership with London Walks
11.00 London Blind Society visit
Saturday 21stApril
10.40 heritage boat trip from Embankment tube offered in partnership with London Walks