Budapest later, with the help of the Russian Empire. 1867 was the year of Reconciliation that brought about the birth of Austria-Hungary. This made Budapest the twin capital of a dual monarchy. It was this compromise which opened the second great phase of development in the history of Budapest, lasting until World War I. In 1849 the Chain Bridge linking Buda with Pest was opened as the first permanent bridge across the Danube and in 1873 Buda and Pest were officially merged with the third part, Óbuda (Old Buda), thus creating the new metropolis of Budapest. The dynamic Pest grew into
Budapest Memorandum on Security Assurances or political independence of Ukraine, Belarus and Kazakhstan. As a result, between 1994 and 1996, Belarus, Kazakhstan and Ukraine gave up their nuclear weapons. Before that, Ukraine had the world's third largest nuclear weapons stockpile, of which Ukraine had physical if not operational control. The use of the weapons was dependent on Russian-controlled electronic Permissive Action Links and the Russian command and control system. Following the annexation of Crimea by the Russian Federation in 2014, the US, Canada, the UK, along with other countries, stated that Russian involvement was a breach of its obligations to Ukraine under the Budapest Memorandum,