The European Union's unity, solidarity, and international reputation are in danger due to various factors such as Greece's debt, Russia's involvement in Ukraine, Britain's desire to alter its relationship with the EU, and migration in the Mediterranean. Failing to address any of these issues adequately would exacerbate the others, increasing the risks facing the European project. The most immediate threat comes from Greece's potential default and the possibility of a "Grexit" from the euro currency, challenging the idea of closer integration among European countries. According to Fabian Zuleeg and Janis Emmanouilidis, a Grexit would have long-term consequences for the EU and could set a negative precedent, undermining the EU's fundamental purpose. Even though Greece only makes up a small portion of the euro zone's economy and population, its recent state bankruptcy following substantial bailouts has dealt a significant blow to the EU's reputation. Before the results of the Greek referendum were revealed, tensions were high in Brussels with blame being placed on various parties. Despite the uncertain future for Greece, it has already proven that the belief in the euro being unbreakable was misguided. Now, efforts may be made to strengthen the remaining members of the euro zone and address flaws in the monetary union, although resistance from Germany could hinder progress. The Greek situation will serve as a cautionary tale for future economic challenges within the euro zone. Destabilizing Greece's economy could worsen Europe's other crises and potentially unsettle the fragile southern Balkans. With existing tensions in the eastern Mediterranean due to conflicts in Syria and unresolved issues like the Israeli-Palestinian conflict and disputes over gas fields, a collapsed Greece might turn to Russia for assistance. This could lead to Greece blocking EU sanctions against Moscow or providing access to naval facilities once used by the US. Additionally, Greece is already struggling with an influx of refugees from Syria and Iraq who are trying to reach Germany or Sweden for asylum. Imagining a scenario where a government expelled from the euro zone uses migrants to exert pressure on EU countries is not difficult. The refugee crisis has caused tensions within the EU, with Italy and other countries on the front lines criticizing their northern and eastern counterparts for not showing solidarity by refusing to share the burden of refugees. Britain has also declined to accept any refugees. The failure to resolve Greece's debt crisis after five years has made the EU appear weak and divided in the eyes of leaders such as Russian President Vladimir Putin and Chinese President Xi Jinping. Brussels officials admit that the euro zone crisis has led to a return to national decision-making on certain policies and weakened Europe's model of rules-based supranational governance. The EU's position in global trade and climate change talks has been weakened by Britain's push to renegotiate its membership terms and hold a referendum by 2017. This raises the possibility of the EU losing a major economy, financial hub, and military power. Despite polls showing support for staying in the EU, there is anxiety in Brussels due to past inaccuracies in UK polling. Ever since winning, Cameron has faced challenges from Eurosceptic rebels within his Conservative party. The ongoing Greek economic crisis, whether within or outside the euro zone, could bolster the argument that the UK economy is closely tied to a failing system. Russia, with its Cold War animosity towards Britain, would likely welcome the UK leaving the EU, as it would weaken the EU's stance against Russian actions in Ukraine and Georgia and could potentially strain its relationship with the US. Despite this, Britain would still remain a member of NATO. This shift could potentially give Putin an advantage in negotiations with German Chancellor Angela Merkel, who has been leading European efforts to resolve the conflict in Ukraine. Rem Korteweg from the Centre for European Reform likens the interconnected crises to the four horsemen of the apocalypse in the New Testament Book of Revelation, symbolizing conquest, war, famine, and death. In an essay, Korteweg stated that EU leaders will struggle to control these threats, and without a unified European response, chaos and instability will persist in the EU.