Agbar Tower, Barcelona

Conceived by famed French architect Jean Nouvel and his team, the 38-story Agbar Tower is a monument to art and sustainability. Sustainable materials, temperature-regulating windows and computer-directed elevators combine to create this iconic symbol of Barcelona. Visitors to the tower should also take note of the fact that the amazing structure has no indoor columns. The view from almost any floor is truly spectacular, providing a vista of all of the points of interests in the city, including Gaudi's Sagrada Familia. Though the view from the interior is breathtaking, the exterior of the tower is just as wonderful to behold. Over 4500 windows cover the tower in its entirety, and all of them can be lit by LED lights in dazzling displays of color and design. There is a souvenir shop on-site where visitors can purchase T-shirts as well as more high-end gifts.