1622 Spanish Gold & Butterflies: Mel Fisher Treasure Museum & Butterfly Conservatory

From the 1600s to the 1800s, Spanish treasure fleets and merchant ships sailing from Havana back to Europe had to thread the hurricane-swept Florida Straits past Key West's shallow coral reefs, causing hundreds of shipwrecks. By the 1850s, licensed maritime salvage ('Wrecking', rescuing passengers and cargo from stranded vessels) made Key West the wealthiest city per capita in the United States. Today, three attractions between Mallory Square and the Southernmost Point bring that heritage and tropical nature to life.

1. The Mel Fisher Maritime Museum (200 Greene Street, Touch Real 1622 Gold)

On 6 September 1622, a hurricane slammed the 28-ship Spanish Tierra Firme Treasure Fleet onto the reefs 35 miles west of Key West, sinking the galleons Nuestra Señora de Atocha and Santa Margarita with 40 tonnes of gold and silver. After searching for 16 years under his daily motto 'Today's the Day', treasure hunter Mel Fisher discovered the Atocha Motherlode on 20 July 1985, the richest shipwreck find in history.

• What You See Inside: lift a real 1622 solid gold bar inside a security box, admire 70-carat uncut Colombian Muzo emeralds, a gold chalice, 10-foot gold chains, astrolabes and 35-kilogram silver ingots, plus exhibits on the 1700 slave ship Henrietta Marie.

2. The Key West Butterfly & Nature Conservatory (1316 Duval Street)

At the quiet southern end of Duval Street (two blocks from the Southernmost Point Buoy), step inside a climate-controlled glass conservatory filled with waterfalls, orchids and mist where over 1,000 free-flying butterflies across 50 to 60 species flutter alongside colourful finches and two resident American Flamingos, Rhett and Scarlet. Wear bright colours so butterflies land on your shoulders.

3. The Shipwreck Treasure Museum & Key West Aquarium

On Mallory Square plaza, climb the 19.8-metre (65-foot) wooden Wreckers' Lookout Tower at the Key West Shipwreck Treasure Museum and visit the open-air 1934 Key West Aquarium (built by the WPA) to see horseshoe crabs, conchs and nurse sharks.