(water trickling) (gentle string music)
October 28th, 2018,
the pictures of the high tide in Venice
go viral around the world.
This is nothing new for the Venetians,
who are used to it, (water sloshing)
but the intensity of the storm
caught everyone off guard, even the organizers
of the Venice Marathon.
Despite last minute changes to the starting time
and route, they couldn't but give participants
an experience they'll never forget.
(soft string music)
It had been 10 years since a high tide
had exceeded the threshold of 1.5 meters above sea level.
On October 28th at 2:00 p.m.,
75% of the city was underwater.
The usual solutions, such as walkways,
pumps and barriers, were not enough this time.
(water sloshing) (eerie music)
(people chattering)
Inevitably, restaurant goers
were forced to eat their pizza
with their feet in the standing water.
(eerie music)
Even the mosaics of San Marco were covered
by the saltwater, which gradually arose
up the walls of the basilica and attacked the frescoes.
(eerie music) (water sloshing)
The city superintendent's monument said,
"Venice has aged 20 years in one day."
(eerie music)
This is nothing compared to the damage
caused by the November 1966 flooding.
(eerie music)
(speaking in foreign language)
In just a few hours, the water rose
by almost two meters, and the tide took control
of the city for almost 18 consecutive hours.
(speaking in foreign language)
It was an unprecedented alarm bell.
To save Venice, it was essential to control the tide
coming into the lagoon from the open sea,
but how could this be done?
(eerie music)
Only a system of floodgates at the four lagoon entrance
that could protect the city from floodings.
Two at Lido Inlet, one at Malamocco, and one at Chioggia.
(eerie music)
This solution, called MOSE, is based on an idea
that is as simple as it is innovative.
It consists in 78 flap gates like these.
They weigh nearly 330 tons each,
and will normally lie on the bottom of the lagoon.
(eerie music)
When needed, the flap gates can be pumped with air
until they rise in a straight line,
blocking the flow of the tide coming in.
Despite its simplicity, the MOSE is the most ambitious
and complex hydraulic engineering project
ever attempted in the world.
(eerie music)
(water rushing)
Here, we're at the Malamocco construction site,
where this metal structure called grasshopper
has just finished positioning a flap gate.
The pontoon is on its way to pick it up
and move it to the spot
where it will lower the following one.
The pontoon, loaded with the next flap gate,
must make for the moment of calm between tides
before slipping under the grasshopper.
The first step is to secure it to the buoys
positioned at the four cardinal points using steel cables.
With the help of winches, the cables
will keep the pontoon still
in its position under the grasshopper.
(people chattering)
Now, the technicians can extend the heavy steeled structure
until it slots into the rail of the grasshopper.
(machine rattling)
The noise of the generators is deafening.
This is why the hooking operations
are directed by small conventional hand gestures
that guide and correct the maneuvers.
The maneuver itself requires the utmost precious,
because there is no room for mistake.
The movements of the structure are constantly obstructed
by the currents or by passing ships,
so much so that it needs a constant adjustment.
(water rushing) (machines rumbling)
The hooking has been completed, and two large pivots
hold the structure and the grasshopper joint together.
(hammer clanking)
Now, the workmen hook the four legs
with strong steel cables, and the entire grasshopper
is slowly raised from the seafloor,
and lifted by more than one meter.
(man yelling in foreign language)
(machine scraping)
Now that the pontoon and the grasshopper are one,
the structure can be moved with the help of the winches
until it reaches the position
where a new flap gate needs to be lowered.
A passing ship makes their work even harder.
Sophisticated electronic devices measure
the position of individual elements
and allow the control room to guide the descent
with millimeter accuracy.
(people speaking in foreign language)
The legs must be lowered slowly until they rest
in the designated points
on the large reinforced concrete platform.
The 330 ton flap gate must be gently submerged.
The descent needs to be perfectly controlled
to allow the hinges attached to the flap gates
to simultaneously lodge into the steel slots
in the reinforced concrete.
It took years to assemble
the concrete platform on the seafloor.
The individual components that make up the platform
have been built here in this site on the mainland.
The engineers call them caissons.
They may look like simple four story buildings
under construction, but each and every detail is special,
from the concrete to the steel,
all elements must endure the saltwater,
but the best part, when these giant caissons
need to be lowered into the sea
and transported, is yet to come.
Each caisson weighs 24,000 tons and requires
a special trolley fitted with pistons,
which is capable to raise them
and gently move them to the launch pontoon.
Then, once it is semi-submerged, like an iceberg,
the caisson is dragged by the tugboats
until it reaches its final home.
(eerie music)
This is its most delicate phase,
the caisson needs to be lowered slowly until it rests
on the ballasts that have been prepared
on the seafloor to house it.
(soft music)
It needs to be aligned with the previous one
in such a way that the trimming between one caisson
and the next is completely watertight.
(soft music)
The platform has been designed to contain
an underwater tunnel that crosses the entire stretch of sea.
(soft music)
Here, the technicians can go down
and fix the hinges of the flap gates.
(soft music)
But let's return to the surface.
The grasshopper is once again firmly on its legs,
ready to receive the flap gate that has been waiting
on the pontoon until now.
(soft music)
The trolleys turn it around
and take it under the grasshopper,
which will finally be maneuvering it.
(soft music)
The workmen carefully wash and lubricate
the anchorages, then, the beam is lowered
to allow the hooks to be positioned
at the designated slots.
A small rotation, and there we are.
The beam is firmly hooked.
(soft music) Attention.
(machine rumbling)
Now, the hydraulic lifts come into play,
raising the flap gate and freeing the trolleys.
(machine rumbling) (soft music)
The pontoon has finished its task.
It is free to set off back to the base.
The day is coming to an end,
but for the workmen, the job isn't finished yet.
First, they must recover and roll up the ropes.
It's a tricky task that for months they've been repeating
with skillful movements each time they position a new gate.
(speaking in foreign language)
This evening, though, they're in the mood
for a celebration, it's the eve
of the end of the works here in Malamocco.
It's the right occasion for a photo
to celebrate the long days spent
in this corner of the lagoon.
The men are thinking about the finishing line
that lies ahead. (speaking in foreign language)
Tomorrow is the big day when the last flap gate
on this inlet will be laid.
(soft music)
Just in time for the Feast of the Redeemer.
(soft music)
The following morning, however,
the weather has suddenly changed.
(eerie music)
The operation to install the last flap gate,
number 19, gets off to a bad start.
(speaking in foreign language)
When the flap gate is gradually being lowered,
the weather deteriorates further.
(waves crashing) (eerie music)
The wind picks up and pushes the waves
straight up the canal. (eerie music)
(speaking in foreign language)
(eerie music)
The risk is too great,
and the engineers decide to give up.
They do so reluctantly, like those who haven't completed
a task before a celebration.
(speaking in foreign language)
What's more, the next day
it's impossible to work even if they want to.
(speaking in foreign language)
Because of the feast, the canal will be full of boats,
and inevitably, the flap gate will have to remain there,
hanging from the grasshopper,
at the mercy of the elements until the celebration is over.
(eerie music)
Despite the forecasts, the first rays of sunlight
shine on a cruise ship loaded with passengers
that are looking forward to enjoying the show
of what's the most beloved celebration for Venetians.
The vessel slides past the grasshopper,
which compared to this giant of the sea
seems unusually small, folded on itself,
as if it were ashamed of that last hanging flap gate.
It's as if it knew that Venice needs protecting.
(eerie music)
(people chattering)
The town is bustling with preparations.
The Bridge of Barges on Giudecca Canal is ready.
The faithful and tourists cross it to thank the redeemer
for putting an end to the plague
that starting in 1565 decimated the population.
(bells ringing)
(bright classical music)
To this day, there are crowds of Venetian boats.
(bright classical music)
They eat, drink and dance
to celebrate the return to life,
waiting for the main event at night.
(bright classical music)
An incredible firework display illuminates the sea
opposite San Marcos Square, which is filled beyond belief
with all kinds of boats.
(fireworks blast) (bright classical music)
(soft piano music)
On Monday morning, the weather conditions
are finally perfect. (gentle classical music)
The divers swim underwater to prepare the slots
that will host the hinges.
(speaking in foreign language)
(tense music) (air bubbling)
The divers must also position
the video cameras that allow the control room
to follow the most delicate phase of the descent live,
the hooking of the hinges.
(water trickling) (speaking in foreign language)
The jacks go up and down.
The cables gradually lower the flap gate
according to an asset that allows the hinges
to perfectly slide into the slots
that are ready to fit it.
(speaking in foreign language)
The video cameras film this decisive moment.
The technicians have to constantly make small adjustments
to compensate for all external interference.
(ship horn blaring)
The hinges at the heart of the system
and the technicians know this well.
All electronic connections with the flap gate
pass through them.
(speaking in foreign language)
It's touch down, but it's not over yet.
It's now time for the technicians in the sea tunnel
to complete the hooking.
The piston rises an inch and fuses into the hinge
a hammer hook that by rotating 90 degrees,
secures it to the platform.
(piston humming) (gentle music)
A message arrives from underwater.
(speaking in foreign language)
It's perfectly watertight, operation over.
This step is finished too.
(speaking in foreign language)
(people applauding)
All 19 flap gates are in place.
To release tension, they celebrate
with a glass of Prosecco, from Veneto, of course.
Where else?
(people speaking in foreign language)
(bright music)
The MOSE is a major tech hub where experimentation
constantly provides new solutions.
(soft music)
This prototype, called jack-up, is the latest one.
It was devised to overcome all issues
that had previously emerged.
It's basically a floating and semi-mobile grasshopper
that can load the flap gates directly from the pier.
Its strange C-shape was studied
to lock with the end of the pier
and allow the trolleys to carry the flap gate
right under the raising structure of the jack-up.
(soft music)
In this way, it can be hooked and raised
from the pier directly, saving time
and avoiding complex maneuvers at sea.
(soft music)
The ace in the hole of this vessel
are its four powerful hydrogen engines.
Independent and able to rotate 360 degrees,
they allow the jack-up to perform
extremely precise maneuvers, avoiding the need
to anchor to keep a position.
And here is the second ace in the hole.
Having reached its position,
the computer onboard can neutralize
the effects of the currents, and even movements
caused by passing ships.
(soft classical music)
Finally, the jack-up can lower the legs.
(machine whirring)
A system of hydraulic jacks accompanies them
until they reach the allocated slots
on the underwater platform and gradually,
the entire vessel rises from the sea
by more than one meter.
(speaking in foreign language)
At this point, the technicians can lower the flap gate.
(soft music)
Hanging from four steel cables,
it descends slowly, guided by the spring jacks.
(soft music)
The operations that previously were directed
remotely from the control room can now be controlled
directly from the bridge of the jack-up.
(soft music)
By the end of the year, all mobile barriers
are scheduled to be in place.
(soft music)
The first tests on those already installed have started.
(eerie music)
But it will be many months of tuning and testing
of the entire system before the MOSE is operative.
(plaintive music)
Only then will the world discover
if this colossal megastructure can save Venice
and its ancient beauty.
(soft music)