These locations are based off of Wiki's Wonder's of the World article. (Crossed out = doesn't exist anymore. Checked off = visited.)

Ancient world:

• Great Pyramid of Giza
• Hanging Gardens of Babylon
• Statue of Zeus at Olympia
• Temple of Artemis at Ephesus
• Mausoleum of Maussollos at Halicarnassus
• Colossus of Rhodes
• Lighthouse of Alexandria

Medieval world:

• Stonehenge
• Colosseum
• Catacombs of Kom el Shoqafa
• Great Wall of China
• Porcelain Tower of Nanjing
• Hagia Sophia
• Leaning Tower of Pisa

Natural world:

• ✔ Grand Canyon
• Great Barrier Reef
• Harbor of Rio de Janeiro
• Mount Everest
• Aurora
• Parícutin volcano
• Victoria Falls

Underwater world:

• Palau
• Belize Barrier Reef
• Great Barrier Reef
• Deep-Sea Vents
• Galápagos Islands
• Lake Baikal
• Northern Red Sea

Industrial world:

• SS Great Eastern
• Bell Rock Lighthouse
• ✔ Brooklyn Bridge
• London sewerage system
• First Transcontinental Railroad
• Panama Canal
• Hoover Dam

Modern world (according to American Society of Civil Engineers):

• Channel Tunnel
• CN Tower
• ✔ Empire State Building
• ✔ Golden Gate Bridge
• Itaipu Dam
• Delta Works/Zuiderzee Works
• Panama Canal

Modern world (according to New7Wonders Foundation):

• Great Wall of China
• Petra
• Christ the Redeemer
• Machu Picchu
• Chichen Itza
• Colosseum
• Taj Mahal

Modern World (according to USA Today):

• Potala Palace
• Old City of Jerusalem
• Polar ice caps
• Papahānaumokuākea Marine National Monument
• ✔ Internet
• Maya ruins
• Great Migration of Serengeti + Masai Mara

I don't travel much now but I plan on it in the future.