At 300m (984ft) and 60 floors the Abeno Harukas skyscraper is Japan's tallest building as of 2020. Completed in 2014 and with exterior designed by well renowned architect César Pelli, who designed several other buildings in Osaka as well as Petronas Towers, the Harukas is famous for its top floor observation decks where especially the sunset and night views are nothing short of spectacular.
The 58th floor open air cafe is a great place to sit back and take in the views with the 59th and 60th floors being 360 degree viewing platforms with floor to ceiling windows for excellent and unobstructed views of the city. You can even opt for a special tour up to the helipad to truly be at the top of the building or walk the edge at 300m strapped into a safety harness...
Abeno Harukas is part of Tennoji station, one of the major transportation hubs in south central Osaka. The municipal subway, JR lines, Kintetsu Railway, and the Hankai tram all come together here and for many going to and from Kansai International Airport this will be one of the points for transfer trains.
The Osaka Mariott Miyako Hotel, Kintetsu department store (the largest in Japan), Abeno Harukas Museum and many other shops and facilities are located in this huge complex.
Both Tokyo Skytree and Tokyo Tower are taller though they do not count as buildings but rather as structures - or as we in Osaka call them: antennas. ;)