What are “hard” and “soft” targets?

Terrorists may select “soft” or lightly protected targets over “hard” or very secure targets.
Potential terrorist targets might include:
HARD TARGETS:
Seats of government
Key industries
Bridges, subways, tunnels, and other key transportation facilities
Water supplies and utilities
Places of historical significance
SOFT TARGETS:
Terrorists may also be drawn to major events such as parades or athletic and entertainment events.