Search for Treasure
Archaeologist (and mother of six) Fiona Haughey leads two-hour trawls along the muddy banks of the River Thames. Previous searchers have taken home Elizabethan pipes, Tudor tiles, and even horse teeth. walks.com, beachcombing walk $12, all ages.
Commune With Monkeys
About 200 wild Barbary macaques roam Gibraltar's Upper Rock Nature Reserve, where curious animal lovers can observe the unfazed primates from up close. (But don't try to slip one a banana—it'll earn you a $745 fine.) gibraltar.gov.uk, free, all ages.
Make Your Mark
Since 1980, political dissidents and graffiti taggers have been layering Beatles lyrics and peace slogans onto the John Lennon tribute wall in Prague's Lesser Town. Today, your budding artists—or activists—are encouraged to add their notes to the mix. Grand Priory Square, free, all ages.
Act Like a Miner
Visitors to this 16th-century German salt mine, 93 miles southeast of Munich, slip into traditional miner's coveralls before sliding down a 100-foot wooden chute for a 75-minute guided tour of the tunnels. berchtesgaden.de, adults $18, kids $12, ages 4 and up.
Fight Like a Warrior
Young fighters-in-training don leather tunics and learn how to spar with wooden swords during two-hour private gladiator lessons on the Appian Way, where Spartacus led his rebellion in 73 B.C. gsr-roma.com, $30, ages 6 and up.