There's new vitality in these cities with ancient roots

CARDIFF, WALES
Why
Europe's youngest capital city boasts Roman ruins such as Cardiff Castle, in its center. You'll see the juxtaposition of old and new by strolling the pedestrian-friendly city—shoppers should hit St. Mary's Street, a stone's throw from the castle—or by stopping at the Wales Millennium Centre for an opera, ballet, or dance performance. The four-year-old theater is part of the redevelopment of Cardiff Bay, a former coal-export hub that is now a scene of shops and restaurants.

Room
With its enormous lobby clock, the Park Inn Cardiff City Centre is reminiscent of a train station and a welcome respite from all the bustle (44-29-2034-1441; cardiff-city.parkinn.co.uk; doubles, $134–$409). The minimalist Big Sleep is housed in a converted 1960s office building (44-29-2063-6363; thebigsleephotel.com; doubles, $74–$102).

Lunch & Dinner
People-watch while lunching on croque monsieur or boeuf bourguignon at Café Rouge, a bistro in Mermaid Quay (2 Mermaid Quay; 44-29-2049-7638; entrées, $13–$28). At the intimate Aegean Taverna, the moussaka melts in your mouth and the stiphado will leave you as stuffed as the grape leaves (117 Woodville Rd.; 44-29-2034-5114; entrées, $16–$52).

Tip
Tradition meets modern-day convenience for those who can't wait until Sunday for a roast with all the trimmings. Ring-a-Roast delivers this adored British meal straight to your door—er, hotel—at a reasonable price (44-29-2023-0123; ring-a-roast.com; entrées, $8–$16).

XI'AN, CHINA
Why
Famous for its terra-cotta warriors, Xi'an has many splendid sights dating to its royal epoch. The 400-year-old Gao Fu House has a theater featuring shadow puppets (200 Bei Yuan Men Xi; 86-29-8723-2897). The 600-year-old Chenghuang Temple, partly destroyed by the Red Guards in 1966, has been restored (West St.). At the Shaanxi Historical Museum, a new exhibition showcases 1,400-year-old Tang murals from royal tumuli (91 Xiao Zhai Dong Lu; 86-29-8525-4727; sxhm.com).

Room
Rooms in the renovated North Wing of the Golden Flower Hotel are no-frills but are spacious and comfortable (86-29-8323-2981; shangri-la.com; doubles, $88–$120). Near the town center, the Sofitel on Renmin Square has bright, compact rooms and great breakfasts (86-29-8792-8228; renminsquare.com.cn; doubles, $96–$110).

Lunch & Dinner
Set menus at Ziao Mai Yuan Fanzhuang feature memorable north Shaanxi dishes, dominated by barley, beans, potatoes, and lamb (58 Han Guang Nan Lu; 86-29-8827-8027; prix fixe, from $30). Have a banquet of dumplings in different shapes and stuffed with a variety of fillings at De Fa Chang Jiaozi (West St.; 86-29-8721-8187; prix fixe, from $20).