Ukrainian naval band plays ‘Don’t Worry, Be Happy’ next to sandbags in Odesa

As the residents of Odessa, Ukraine, weigh whether or not to flee their homes and watch as Russia's military encroaches further into their country, a military band decided it would try to lighten the mood with a familiar tune.

With sandbags and anti-tank weapons as their stage settings, a group of Ukrainian naval musicians gathered to play Ukraine's national anthem, as well as Bobby McFerrin's 1980's hit "Don't Worry, Be Happy."

Odessa has been lucky so far, as it is largely insulated from the Russian military's land advances. It is a valuable port city with access to the Black Sea, and will likely be a target if the invasion is not stopped.

However, its position on the Black Sea makes it vulnerable to attacks from the water. Directly across from the city on the eastern edges of the Black Sea is the Crimean Peninsula, which was annexed by Russian President Vladimir Putin in 2014.

The Ukrainian navy's headquarters on the Black Sea were formerly in Sevastopol, but moved to Odessa following the annexation.

While Mr McFerren's iconic song is a good reminder not to sweat the small stuff, he was singing about his rent being late and having his bed stolen, not surviving a naval assault from a nuclear-armed military superpower.

For residents of Odessa, the cause for worry is playing out in other cities around the country. Civilians trying to evacuate have been killed in Kyiv. Kharkiv has reportedly been taken over by Russian forces, and Mariupol is under siege, leaving residents struggling to find food and medicine with no safe route for evacuation.

The Russian military has already taken the port city of Kherson, just 75 miles (120km) east of Odessa, and Russian ships have reportedly been spotted near Ukrainian territorial waters.

Ukrainian President Volodymyr Zelenskyy said Sunday that Russia was planning to attack the city, which he said would be a "historic crime”.

The Ukrainian military has set up defenses around the city – including the sandbags that served as a backdrop for the Navy band – and is preparing to defend Odessa from a likely Russian assault.

If Odessa does fall to Russia, Ukraine will lose its last large port on the Black Sea, cutting it off from a crucial ingress point for supplies. Russia reportedly wants to take the city intact, as it is both a strategic war asset as well as culturally and historically significant to Russia. The city was founded by Russian Empress Catherine the Great and was a cosmopolitan centre during the country's first imperial era.