Massively extended in the 1970s and with a second terminal added in the 1980s, Frankfurt Airport (FRA) is now one of Europe's busiest and most important airports. Known as the 'gateway to Europe', passengers from all over the world arrive, depart or change planes here. A plane takes off or lands every two minutes and around 45 million people pass through the airport every year. Around 108 airlines fly to and from Frankfurt. With some 14,000 underground parking spaces, parking at Frankfurt Airport is not a problem. Apart from the usual airport amenities like shops and a multitude of restaurants and bars, there is also an airport clinic, a play area, a prayer room and dog kennels. The airport is connected to Frankfurt city center by S-Bahn (regional railway) and by express trains which depart from the airport station every 15 minutes.