answers: Heathrow Airport
context: Helsinki Airport Helsinki Airport (; , ) is the main international airport of the city of Helsinki, its surrounding metropolitan area, and the Uusimaa region. The airport is located in the city of Vantaa, about west of Tikkurila, the administrative center of Vantaa and north of Helsinki city center. The airport is operated by state-owned Finavia. The airport is the largest in Finland and the fourth busiest in the Nordic countries in terms of passenger numbers. About 90% of Finland's international air traffic passes through Helsinki Airport. The airport handled close to 19 million passengers in 2017, including 16.2 million </s> Düsseldorf Airport Düsseldorf Airport (, ; until March 2013 "Düsseldorf International Airport"; ) is the international airport of Düsseldorf, the capital of the German state North Rhine-Westphalia. It is located approximately north of downtown Düsseldorf, and some south-west of Essen in the Rhine-Ruhr area, Germany's largest metropolitan area. Düsseldorf is the third largest airport in Germany after Frankfurt and Munich handling 24.5 million passengers in 2017. It is a hub for Eurowings and serves as a focus city for several more airlines. The airport features three passenger terminals and two runways and is able to handle wide-body aircraft up to </s> 75 million international passengers annually, is the largest airport in the UK. London serves as the largest aviation hub in the world by passenger traffic, with six international airports, handling over 163 million passengers in 2016, more than any other city. London's second-busiest airport, London-Gatwick, was until 2016 the world's busiest single-runway airport. Manchester Airport is the United Kingdom's third-busiest airport. London-Stansted and London-Luton are the fourth- and fifth-busiest airports, respectively. The largest airport operator in the United Kingdom is Heathrow Airport Holdings (owner of Heathrow), followed by Manchester Airports Group (owner of Manchester, Stansted and East Midlands). Together with
question: which one is the biggest airport in europe