Also our pick for the most luxurious hotel in Vienna, Palais Hansen has all the bells and whistles of a hotel that's set for romance. From the sexy subterranean spa, to the beautiful Michelin-starred restaurant, it caters to couples, who will also appreciate the gorgeous rooms; decked out in rich natural materials, they all have Nespresso machines and iPad controls.

Rooms at the Imperial are truly decadent, and some find them even more romantic than the more modern accommodations at Palais Hansen. However, this beautiful property comes in second since it lacks a spa -- although it does have a sauna. Other romantic features include a great restaurant and cafe, a bar and salon with live classical pianists, and personal butlers who cater to guests staying in suites.

The Ring, a boutique property in the heart of Vienna, creates a romantic atmosphere by blending classic 19th-century elements with sleek modern decor. While neutral-toned rooms may not seem quite up to the romance level of those at Palais Hansen and Hotel Imperial Vienna, this hotel does have a full-service spa, as well as a wine cellar with private tastings and a fine-dining restaurant with a cocktail bar.

A quiet boutique, lacking even a formal lobby, Hotel Altstadt makes for a romantic retreat. The 45 large rooms are individually decorated, and some are sexier than others -- like the Felix Suite with an exposed bathtub in the bedroom. A vast private art collection also gives the spaces a more romantic vibe, and couples can enjoy perks like free breakfast, and free afternoon teas and cakes.

Hollman Beletage is a design-centric boutique with bright, airy rooms; some are more spacious than other, and all have plush bedding, flat-screen TVs, free Wi-Fi, and minibars. An on-site spa is a romantic touch, as is a slew of freebies such as breakfast, afternoon snacks, and a daily fruit plate delivered to rooms.