The tranquil waters of the Mediterranean
are often seen as a place for sun, sea and relaxation.
But far from shore, there's a brewing diplomatic crisis
that is stoking fears of conflict
at the borders of the EU.
It's driven by energy reserves, territorial rivalries,
and longstanding political disputes
in a region already roiled by war in Libya
and the fraying relations between European countries
and Turkey's president Erdogan.
At the heart of the trouble are competing claims
for territory that have long simmered in the background.
The discovery of natural gas reserves
has brought them back to the surface.
Most of the disputes centre on competing claims for the land
around the Greek islands, Turkish coastline and Cyprus,
a divided island.
Peace talks have repeatedly failed
to reunite the Greek Cypriot south with the north, which
was occupied by Turkey in 1974 with the justification
of protecting the island's Turkish-speaking minority
after a Greek-backed coup.
The discovery of huge gas reserves in the last two
decades, combined with the shifting
politics of the region, threatens
to bring this crisis to a head.
First Israel, then Egypt, discovered
significant resources that had the potential
to transform their energy-poor economies while leaving them
with enough gas left over to export to other countries.
The issue with this, is that some of the territory
is disputed.
Turkey believes that Northern Cyprus,
which is not recognised internationally
as an independent state, is entitled to share the economic
benefits of any gas finds around the island and should be able
to determine who can drill in the water around its northern
part.
The government on the Greek Cypriot side is recognised
as the legitimate authority for the whole island by every other
country in the world and the EU, which controversially admitted
Cyprus as a member in 2004, despite its divided status.
Turkey also believes that Greece's claimed maritime
border is being unfairly distorted
by tiny Greek islands, which it doesn't believe
should have the same maritime rights in international law
as countries with vast coastlines.
It believes that international case law is on its side.
Although, Turkey is not a member of the UN
Convention on the Law of the Sea.
If you look at the maps here, you can see Cyprus's declared
exclusive economic zone, based partly on negotiated agreements
with its neighbours that are internationally recognised.
But when you overlay this second map, some of the same territory
is claimed by Turkey through its own coastline and some
by Northern Cyprus.
An exclusive economic zone is an area prescribed by the UN.
It's generally taken to be up to 200 nautical miles
off the coastline and gives a country
exclusive or special rights over the exploitation of resources
in that area.
Where two countries' zones overlap,
the territory is generally cut along a median line
between them.
The south and eastern parts of Cyprus's zone, shown here,
are delineated by agreements with Egypt, Israel and Lebanon.
Turkey believes that its claim should
extend further from its coastline beyond Cyprus itself.
Greek islands, such as those in the Aegean Sea
that lie very close to its coastline,
should not be automatically entitled to a full zone,
and that countries should instead
negotiate an equitable solution that is fair to all parties.
You can see on the map here that Cyprus is essentially
encircled by the Northern Cyprus and Turkish claims,
apart from one small area to its southwest.
In recent weeks, Turkish drillships
supported by the Turkish military
have returned to disputed territory in the west of Cyprus
to drill for gas.
The move has faced resistance from Greece,
France, and some other EU nations
who believe that Turkey's actions are provocative.
Germany has led an effort to try and cool tensions.
Crucially however, where Turkey is drilling,
is not in the area where gas reserves have yet
been discovered.
Off Cyprus, the country has decided
to auction a number of blocks of territory
to international energy companies to come and explore.
They do this by putting a price on what
they think are the most likely areas to contain gas.
One of the issues for the eastern Mediterranean
is finding a way to get the gas to market.
Israel, for example, has been able
to pipe it directly into the country and use gas
to significantly reduce its reliance
on highly polluting coal, before beginning exports
to Jordan and Egypt.
Egypt has pipelines running from near the giant Zohr gas fields,
which bring the gas ashore.
One of the dreams of many executives working
in the region is to establish a far larger pipeline, known
as the EastMed gas pipeline, to take the gas from near Cyprus
to pipe it towards Greece and Italy
to give Europe an alternative to Russian gas supplies.
However, this would be one of the most ambitious undersea gas
pipelines in history, both in terms of its length,
over 2,000 kilometres, but also the territory it
would need to pass through, some of which
Turkey claims as its own.
The long-term hope is that natural gas reserves
lead to a form of reconciliation between Greece, Turkey
and Cyprus, as they see the benefits of mutual development
of the gas.
Such an outcome has been sought for decades
with little success.
The risk is that by accident or design,
the gas reserves of the eastern Mediterranean
could become a flash point for these wider disputes.