The 19th century saw many different types of architectural innovations, but the most representative structures of that time period are the: Eiffel tower and the Crystal palace. The Eiffel tower started out as an exhibition to celebrate the 100-year anniversary of the French revolution, it became a cast-iron tower that provided tourists with a full view of Paris. The Eiffel Tower combines architectural features of the past, present, and future; also, it brings elements of a gothic church. The Crystal palace was built for the “Great Exhibition in London” in the year 1851 and became one of the first buildings to have both steel and glass in its architecture. The building contained over 18,000 panes and resembled a big greenhouse. These architectural advancements were made possible due to innovation in steel and metal technology; this allowed new structures to be higher than ten stories and allowed elevators to be installed.