The Suwaki Gap could prove a pivotal piece of land for Russian President Vladimir Putin . Photo / Getty
It's one of the most peaceful corners of Europe. Quiet country roads lead through immaculate towns, skim past lakes and wind their way around virginal forests dotted with oak and spruce.
But defence watchers say this thin strip of land, fully within the European Union, could be a flashpoint of future military action between Russia and the US.
A strategic affairs analyst has even raised the prospect that an emboldened Russia, intent on pushing the Washington-led NATO military alliance away from its territory, could drop a nuclear bomb on the isolated sliver of land.
Known as the 'Suwalki Gap', this 80km patch of relatively flat, difficult to defend countryside, straddles Poland and Lithuania.
It is the only land connection between the Baltic states of Latvia, Lithuania and Estonia - all of which are in the EU and NATO - and their European allies.
On either end of the Suwalki Gap is Putin. To the west the Russian exclave of Kaliningrad, stuffed to the gills with nuclear missiles, and to the east Moscow's close ally Belarus.
It's a nightmare pinch point for NATO and its Baltic partners.
"This gap could be easily overcome. Russia has very powerful forces stationed in Kaliningrad and with troops from Belarus it could be quickly closed," Alexy Muraviev, a Russian strategic defence affairs expert from Curtin University told news.com.au.
In 2015, Lieutenant General Ben Hodges, the commanding general of the US Army in Europe speculated on a scenario where Moscow shut the Gap under the cover of a military exercise.
"You get thousands of Russian troops on both ends of the Suwalki Gap, so there's a potential for them to transition from an exercise to an operation - that's our concern."
Indeed, the area has become one of the most militarised in Europe with Russia and the US heavily armed and cheek by jowl.
Emeritus professor of strategic studies at Australian National University, Paul Dibb, said the West's military expansion onto Moscow's doorstep has never sat well with Russia.
"Putin viewed the disintegration of the former Soviet Union as the greatest geopolitical catastrophe of last century. My view is when Russia was on its knees [following the end of the Cold War] it was provocative to expand NATO's borders into the former Soviet stratosphere," he said.
"The distance between the nearest NATO airfield in Estonia to St Petersburg is the same distance from Canberra to Cooma and I can tell you if we had Indonesian jets in Cooma we'd be doing something about it."
Prof Muraviev agreed and added that the Baltic States' independence had deprived Russia of access to strategically vital ports on the Baltic Sea.
Yet, this was precisely the reason why the Baltic States had embraced NATO.
"Russia has had an eye on unimpeded access to Baltic since the 17th century and the Baltics fear Russia annexing them," he said.
While Kaliningrad, next to the Gap, meant Russia still had a presence on the Baltic Sea, it was an imperfect pocket of territory.
Moscow sees the exclave as being vulnerable, surrounded by NATO members. How much easier (and less humiliating) would it be if Russia didn't have to ask permission from Lithuania - formerly part of the USSR - to move troops in and out of Kaliningrad.
Prof Dibb said the instability in European political could encourage Putin to give it a go.
"These are pitifully small countries with pitifully small militaries. They have been rolled over by the Nazis and the Red Army and the temptation for Putin would be there is low hanging fruit for him."
To discourage Putin, the states have strengthened their borders while NATO has sent three battalions of around 3000 troops to the Baltic.
Another 1000 US troops are stationed in eastern Poland close to the Suwalki Gap.
The military boost came after a 2016 report by the US RAND think-tank said without reinforcements it would take Russia just 60 hours to capture the Estonian and Latvian capitals.
Prof Dibb said he doubted NATO's actions would make much difference to a determined Russia. "Putin can deploy 150,000 troops almost instantaneously into any of the Baltic countries. What are three NATO battalions against 150,000 troops?"
He had spoken to a Russia watcher, Prof Dibb remarked, who said it would be unthinkable for a nuclear weapon to be used the Baltics.
But, he was told, a bomb could conceivably be detonated in a more remote area to demonstrate Russia's resolve.
"I said, could that be on the Suwalki Gap to show they were serious? He didn't answer," said Prof Dibb.
If Russia did push into the Baltics and block the Suwalki Gap, NATO would almost certainly have to respond or risk becoming irrelevant. Estonia and Poland are proportionally some of the biggest contributors to NATO.
Prof Muraviev said he doubted Moscow would do a Crimea and annex the Baltics.
"Russia would have no problem overrunning the Baltics but the geopolitical fallout would offset any territorial gains. It would be political suicide."
However, the biggest reason holding Russia back might not be US or European troops stationed on its borders - but the Baltic people themselves.
While there are substantial numbers of ethnic Russians in the Baltics, there are far fewer than in parts of Ukraine.
"Russia would be met at best with neutral hostility and at worst protracted armed [guerilla] conflict. The Soviets experienced this in the Baltics in the 40s and 50s and they don't want it to happen again."
That's not to say war couldn't happen. If NATO moved offensive rather the defensive machinery into the Baltics, or blocked sea lanes or access to Kaliningrad, Putin's troops could mass at the Gap, daring the west to cross.
But, Prof Muraviev fears most what isn't planned for. The accidental escalation that could come with having opposing forces so close to one another.
"There's a mutual vulnerability there, Russians feel vulnerable to NATO forces, the Baltics feel vulnerable to massive Russia. When you have mutual distrust there is an ongoing risk of a military escalation."
NATO says it's determined to keep the Suwalki Gap open.
"We are committed to the sovereignty of Lithuania, the sovereignty of Poland and all the other countries, so we will do whatever it takes to re-establish that," Lt Gen Hodges told NBC.
"It's not inevitable that it goes to a Third World War. Nobody wants that, including the Russians."