Taylor Swift's THE 1989 WORLD TOUR stops in DC

Taylor Swift's THE 1989 WORLD TOUR stopped by Washington D.C. for two concerts at Nationals Park.

One of the biggest moments of Monday night was a surprise guest appearance by Lorde, who joined Swift on stage to perform the song "Royals."

Another memorable moment during the show was when Swift's performance was hit with a technical difficulty. The stage lift that brings her up over the crowd got stuck. However, she was eventually brought down and continued her concert without any other issues.

On Tuesday night, Jason Derulo joined Swift on the stage as the surprise performer.

Many devoted Swifties lined up outside the stadium waiting to get in while showing off their excitement with some interesting signs and wardrobe.

Many others were hoping to buy last-minute tickets for the hottest ticket in town. Although tickets were sold out, there were some available on secondhand ticket selling websites such as StubHub for around $500.

Before Swift hit the stage Monday night, our own Mike Thomas caught the attention of the music superstar with a special weather forecast on Monday morning and she had a special message for him on her Twitter account.

For those attending Tuesday night's concert, Nationals Park reminds fans that you cannot bring in any selfie sticks! See a full list of prohibited items here.

There is a threat of possible severe weather during Tuesday night's concert. Swift tweeted Tuesday evening, "Due to this sketchy weather situation in DC, I'm not sure what time I'll be going on tonight. You might want to get here early."

A Washington Nationals spokesperson tells FOX 5 that the show will go on and said in a statement, "The safety of our guests is of the utmost importance. If severe weather occurs, we are prepared to relocate fans under cover until the storm passes."