The Yarlung Tsangpo Grand Canyon (Tibet) and the Grand Canyon (Arizona) are both colossal, but the Grand Canyon is larger by most measures:
| Metric | Yarlung Tsangpo | Grand Canyon |
|---|---|---|
| Length | ~504 km (313 mi) | 446 km (277 mi) |
| Max Depth | ~6,000 m (19,700 ft) | ~1,800 m (6,000 ft) |
| Avg Width | ~1.6 km (1 mi) | ~29 km (18 mi) |
| Max Width | ~3.2 km (2 mi) | ~34.6 km (21.5 mi) |
| Relief (river to rim) | Up to 5,500 m | Up to 1,800 m |
Verdict: Yarlung Tsangpo is longer and deeper (greatest relief on Earth). Grand Canyon is wider and larger in total volume/area. "Bigger" depends on definition: Yarlung Tsangpo wins on depth/relief; Grand Canyon on breadth and overall grandeur.