The six-month battle for the Ukrainian city of Bakhmut has been the longest and bloodiest fight of the war so far.

Little known outside Ukraine before the Russian invasion, Bakhmut has become a symbol of the country’s fortitude and perseverance in the face of the Kremlin’s onslaught.

The Ukrainian leadership vowed again this week to keep defending the city, but some observers have warned that holding on to it could be too dangerous and costly.

Here is a look at Bakhmut, the battle and its possible consequences.

WHAT KIND OF CITY IS BAKHMUT?

Bakhmut, which had a prewar population of more than 70,000, was an important center for salt and gypsum mining in the Donetsk region of the country’s industrial heartland known as the Donbas.

The city was also known for its sparkling wine production in historic underground caves. Its broad tree-lined avenues, lush parks and stately downtown with imposing late 19th century buildings made it a popular tourist attraction.

When a separatist rebellion engulfed the Donbas in April 2014, weeks after Moscow’s illegal annexation of Ukraine’s Crimean Peninsula, Russia-backed separatists won control of the city but lost it a few months later.

HOW DID THE FIGHTING EVOLVE?

Russian troops first attempted to recapture Bakhmut in early August but were pushed back.

The fighting abated in the following months as the Russian military faced Ukrainian counteroffensives in the east and the south, but it resumed at full pace late last year. In January, the Russians captured the salt-mining town of Soledar just a few kilometers (miles) north of Bakhmut and advanced to the city’s suburbs.

The relentless Russian bombardment has reduced Bakhmut to a smoldering wasteland with few buildings still standing. Russian and Ukrainian soldiers have fought ferocious house-to-house battles in the ruins.

Soldiers from Russia’s private Wagner Group contractor have spearheaded the offensive, marching on “the corpses of their own troops” as Ukrainian officials put it. By the end of February, the Russians approached the only highway leading out of the city and targeted it with artillery, forcing Ukrainian defenders to rely increasingly on country roads, which are hard to use before the ground dries.

WHAT DO UKRAINIAN AND RUSSIAN OFFICIALS SAY ABOUT THE BATTLE?

Ukrainian authorities have hailed the city as the invincible “fortress Bakhmut” that has destroyed waves of Russian assailants.

As Russian pincers were closing on the city, a presidential aide warned last week that the military could “strategically pull back” if needed. But on Monday, Ukrainian President Volodymyr Zelenskyy and his top generals decided that the army will keep defending Bakhmut and reinforce its troops there.

For the Kremlin, capturing Bakhmut is essential for achieving its stated goal of taking full control of Donetsk, one of the four Ukrainian regions that Moscow illegally annexed in September.

Russian Defense Minister Sergei Shoigu said Tuesday that the seizure of Bakhmut would allow Russia to press its offensive deeper into the region.

Yevgeny Prigozhin, the rogue millionaire who owns the Wagner Group, charged that his forces were destroying the best Ukrainian units in Bakhmut to prevent them from launching attacks elsewhere.

At the same time, he harshly criticized the Russian Defense Ministry for failing to provide Wagner with ammunition in comments that reflected his longtime tensions with the top military brass and exposed problems that could slow down the Russian offensive.

WHAT DO EXPERTS SAY?

Military experts note that Ukraine has turned Bakhmut into a meat grinder for Russia’s most capable forces.

“It has achieved its aim as effectively being the anvil on which so many Russian lives have been broken,” Lord Richard Dannatt, the former chief of the general staff of the British armed forces, said on Sky News.

Phillips P. O’Brien, professor of strategic studies at the University of St Andrews, said the battle for Bakhmut “confirms that the Russian army is still struggling with basic operations.”

He noted that the Kremlin’s continuing emphasis on land grabs regardless of losses means that “Russian strategic aims are bleeding the Russian army greatly.”

While Ukrainian and Western officials pointed out that Russian combat losses were much higher than Ukrainian, some observers argued that the defense of Bakhmut was distracting Ukrainian resources that could be used in a planned counteroffensive later in the spring.

Michael Kofman, director of Russia studies at CAN, a Washington-based think tank, observed that the Ukrainian defenders “achieved a great deal, expending Russian manpower and ammunition,” but added that it could be wise for Ukraine to save its forces for future offensive operations.

“Strategies can reach points of diminishing returns,” and given that Ukraine “is trying to husband resources for an offensive, it could impede the success of a more important operation,” he said.

WHAT COULD HAPPEN NEXT?

Ukrainian and Western officials emphasize that a Ukrainian retreat from Bakhmut will not have strategic significance or change the course of the conflict.

The Ukrainian military has already strengthened defensive lines west of Bakhmut to block the Russian advance if Ukrainian troops finally retreat from the city. The nearby town of Chasiv Yar that sits on a hill just a few kilometers west could become the next bulwark against the Russians. Further west are Kramatorsk and Sloviansk, the heavily fortified Ukrainian strongholds in Donetsk.

And even as the Russian military tries to pursue its offensive in Donetsk, it needs to keep large contingents in other sections of the Donbas and in the southern Zaporizhzhia region where Ukrainian forces are widely expected to launch their next counteroffensive.