emergency high hydraulic ladder long metal rescue rungs safety tall platform sky top height heights observation observation platforms platforms poles protection protective railing rails slide stairs steps support supportive tree viewing viewing platforms views attached blue buildings climbing climbing-equipment detached exercise exercise-equipment exercising greenery man metal-rungs metal-work neighborhood neighbourhood park participant plants playground public public-park public-space recreation recreational roofing shade shadows shrubbery soft-blue-exercise-flooring sunlight sunshine trees user