Heidi Montag** and Spencer Pratt** are going global!

The Hills reality stars are currently sightseeing in London, and Montag, 26, has been documenting their every move via Twitter. After touring Buckingham Palace and visiting Big Ben and London Bridge, the spouses of four years "went ice skating and played in red phone booths and taxis," Lauren Conrad''s ex-BFF wrote.

Pratt even took a break from Twitter, he explained, "to recharge my crystals with my wife, Heidi." (In May 2010, a source told Us Weekly the couple spent $400,000 on healing crystals.)

The University of Southern California student also relied on his British Twitter followers for assistance in finding "little bookstores in London where I might find some quality poetry." Pratt added, "I'd like to buy something special for Heidi."

"I'm looking for faves," he explained. "Undiscovered gems! The more obscure the better!" Pratt retweeted a few followers who suggested Backlands Terrace, Waterstones, Pan Bookshop and Peter Harrington, among others.

During their European getaway, Pratt, 29, accidentally misplaced the "new phone" his wife gave him for Christmas. "It's probably in the hotel," Montag told her 1.4 million Twitter followers. According to Pratt, however, "it was lost under Heidi's intimates, tremendous as they are. Thanks for the concern."

This article originally appeared on Usmagazine.com: Heidi Montag and Spencer Pratt Tour London, Visit Buckingham Palace