Budapest's line one metro, which runs through the heart of Pest, is one of the oldest metro systems in the world, second only to London's. Opened in 1896, it runs from Vörösmarty tér to Mexikói út along Andrassy Avenue, the main commercial artery of the city. It's a delightfully retro experience, complete with comically tiny train cars, jerky amusement park-like movements, and charming, barely-underground stations. Definitely a must for visitors to Budapest.
Enjoy this short video I made in tribute: