In the elegant, historic port city of Odesa, residents prepare to fend off a Russian attack

When the air raid sirens go off in the Black Sea city of Odesa these days, there are those who run for the bomb shelters and those who keep going about their business — although perhaps in a slightly more subdued manner.

A Ukrainian colleague compared it to the early days of the pandemic, when streets emptied with expectations of potential disaster and fear of the unknown.

But after a while, people started to appear on the streets in greater numbers as they adapted to their changed circumstances. 

After all, predictions that Odesa's strategic value, as Ukraine's largest Black Sea port and home to its small navy, would make it an early target for the Russians have not come to pass.

Other cities have been bearing the brunt of those early assaults, and so buying Odesa time.

"We understand that while ... Kyiv fights, while Kharkiv fights, while Mykolaiv now fights so bravely, we have this gap to prepare the city," said Inga Kordynovska, a lawyer co-ordinating humanitarian relief from Odesa to front-lines across Ukraine.

The shelves of bars and stalls in the trendy Odesa Food Market are now filled with medicine and warm clothes for front-line soldiers and essential supplies for people trapped by fighting. 

Volunteers in high-viz vests pack boxes or tap away at computers in the market's two-tiered gallery, under a giant red dragon left over from happier times and still hanging from the ceiling.

Kordynovska says the horror of what's unfolded in cities like Kherson, Melitopol and especially Mariupol to the east is a powerful motivator and a unifier for Odesans preparing their city for war. 

"We see that every city where Russian soldiers came, everything was destroyed," she said. "And of course even those people who say they are not [into] politics — [that] it doesn't matter for us, Odesa is a separate city — now they understand that, no, you can't be out of this process. You can't say, 'It's not about me.'"

Some analysts have suggested the reason Odesa has been spared so far — aside from the strong resistance Russian forces have encountered in cities like Mariupol and Kherson — is because the city, founded by the Russian Tsarina Catherine the Great in 1794, holds special significance for Russian President Vladimir Putin.

Whatever the reason, authorities appear determined not to squander the time. Odesa's elegant downtown core is now a closed military zone dressed for war.

WATCH | People in Odesa, Ukraine, prepare for the possibility of a direct fight with the Russian military:

Metal anti-tank obstacles dot city streets, some so big they dwarf passersby, who appear from afar like tiny pieces caught in a giant's board game.