True scale. Scroll to zoom, or press Zoom tour. Each small thing sits next to the bigger one.
| Human sperm, head to tail | ~55 µm |
| Sperm head | 5 × 3 µm |
| E. coli bacterium | 2 × 0.8 µm |
| Smallpox virus | ~300 × 250 nm |
| Influenza virus | ~100 nm |
| Poliovirus / rhinovirus | ~30 nm |