The city's best views can be found on the 65th-floor 360-degree Observation Deck of the landmark Lotte Center in the western corner of Hanoi's Ba Dinh district. From this uninterrupted vantage point, high above Hanoi's hustle and bustle, you can compare the size of the Old Quarter relative to the sheer scale of Hanoi's voracious growth. Glass-floor sky walks allow you to walk out over the precipitous drop. There's also a rooftop bar on the same floor as an alternative.
The tower also houses a hotel, all manner of restaurants and a department store on its lower floors. The Lotte Center is around 20 minutes by taxi from the Old Quarter.