Here are the seven highest mountains in the world, with their approximate heights:

1. Mount Everest (Nepal/China): 8,848.86 meters (29,031.7 feet)

2. K2 (Pakistan/China): 8,611 meters (28,251 feet)

3. Kangchenjunga (Nepal/India): 8,586 meters (28,169 feet)

4. Lhotse (Nepal/China): 8,516 meters (27,940 feet)

5. Makalu (Nepal/China): 8,485 meters (27,838 feet)

6. Cho Oyu (Nepal/China): 8,188 meters (26,864 feet)

7. Dhaulagiri I (Nepal): 8,167 meters (26,795 feet)

Note: The heights can vary slightly depending on the measurement method and the year of measurement.