Rings of Brighthearth, Deserted Temple, and Gaea's Cradle

Prerequisites

• Rings of Brighthearth on the battlefield
• Deserted Temple on the battlefield
• Gaea's Cradle on the battlefield

Steps

1. Activate Gaea's Cradle by tapping it, adding at least Activate Deserted Temple's second ability by paying and tapping it, targeting Gaea's Cradle
2. Rings of Brighthearth triggers, causing you to pay to copy Deserted Temple's ability, targeting Deserted Temple
3. Resolve both Deserted Temple abilities, untapping Deserted Temple and Gaea's Cradle Repeat

Results

• Infinite mana lands you control can produce
• Infinite green mana
• Infinite untap of lands you control