I stepped off the terracotta planter onto the flat concrete ledge of the balcony railing. Sunlight caught a thin brass picture-hanging wire lodged between two metal vertical balusters. I crouched low, gripped the wire, and pulled it taut. Pliant, but remarkably strong. I wrapped the slack three times around a lower horizontal rail bolt, bending the end flat against the metal frame to prevent fraying. Testing the line with a firm downwards press, it held my weight without flexing. A reliable exterior anchor point. Good to map the perimeter.