As the war progressed, British military advisor Sir John Burgoyne recommended fortifying the Dardanelles to prevent a Russian advance on Constantinople. While diplomatic efforts kept Austria neutral initially, it eventually sided with the UK and France, pressuring Russia to withdraw from the Principalities. Despite Russia's withdrawal, hostilities persisted as the UK and France sought to limit Russian influence over the Ottomans. Ottoman forces achieved notable victories on the Danube, while the Allies dominated the Black Sea. In June 1854, Allied forces landed at Varna on the Black Sea but made slow progress. By mid-September 1854, Allied forces landed in Crimea and began their march toward Sevastopol, Russia's main naval base in the Black Sea. A few days later, the Allies clashed with Russian forces at the Battle of Alma, decisively defeating the Russians and killing over 5,700 soldiers. Despite this victory, the Allies failed to capitalize on the Russian retreat, allowing the Russians to fortify Sevastopol and initiating a prolonged siege that would last nearly a year. During this time, the Allies faced significant challenges, including outbreaks of cholera, harsh winter conditions, and strained supply lines. The Russian army, despite heavy losses, continued to reinforce Sevastopol, turning it into a formidable stronghold. The siege dragged on, with notable battles such as the Battle of Balaclava on October 25, 1854, where the British 93rd Highlanders famously held off a Russian cavalry charge in what became known as the "Thin Red Line." However, a miscommunication led to the ill-fated Charge of the Light Brigade, where British cavalry charged directly into a heavily defended Russian artillery position, resulting in significant casualties. As the siege continued, the Battle of Inkerman on November 5, 1854, saw British forces repel a Russian surprise attack despite fighting in thick fog and confusion, leaving behind thousands of Russian dead. Despite these victories, the Allies were unable to break the deadlock, and the harsh winter of 1854-1855 took a heavy toll on both sides, with many soldiers succumbing to disease and exposure. By early 1855, the war showed no signs of abating. In May, the Allies launched a successful invasion of Russian-held Kerch, marking the first use of ironclad ships in naval warfare. However, political pressures in the UK and France made it difficult to find a resolution to the conflict. The turning point came in the summer of 1855 when French forces successfully assaulted the Malakoff Redoubt, a key fortification in Sevastopol's defenses. On September 11, 1855, the Russians, unable to hold the city, blew up their remaining forts, sank their ships, and evacuated Sevastopol. Faced with the threat of Austria joining the war on the side of the Allies, Russia finally agreed to peace terms. On February 1, 1856, Russia accepted preliminary terms, leading to the Congress of Paris, which began on February 25. The Treaty of Paris was signed on March 30, 1856, bringing an end to the conflict. Under the treaty, Russia surrendered southern Bessarabia and accepted the neutralization of the Black Sea. Additionally, the Danube River was opened to international shipping, and the integrity of Ottoman Turkey was guaranteed. Although peace was restored, tensions between Russia and the Ottoman Empire persisted, eventually contributing to their alignment on opposite sides during World War I.